Storage system comprising function for reducing power consumption

ABSTRACT

For at least one of storage unit, processor and cache memory which are I/O process-participating devices related to I/O command process, when a load of one or more I/O process-participating devices or a part thereof is a low load equal to or less than a predetermined threshold value, a processing related to a state of one or more of the I/O process-participating devices or a part thereof is redirected to another one or more I/O process-participating devices or a part thereof, and the state of the one or more I/O process-participating devices or a part thereof is shifted to a power-saving state.

CROSS-REFERENCE TO PRIOR APPLICATION

The present application is a continuation of application Ser. No.13/232,014, filed Sep. 14, 2011, now U.S. Pat. No. 8,261,036; which is acontinuation of application Ser. No. 11/968,797, filed Jan. 3, 2008, nowU.S. Pat. No. 8,041,914; which relates to and claims the benefit ofpriority from Japanese Patent Application number 2007-167325, filed onJun. 26, 2007 the entire disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

The present invention generally relates to reduction of the powerconsumed by a storage system.

Advancements in information technology in recent years have beenaccompanied by a dramatic increase in the volumes of data handled bybusiness computer systems. The resultant increase in capacity andperformance of the storage systems in which the data handled by acomputer system is stored has led to increased storage system powerconsumption. Accordingly, reduction of the power consumed by a storagesystem is desired.

Examples of technologies related to reduction of the power consumed by astorage system are disclosed in Japanese Unexamined Patent ApplicationNo. 2000-293314 and Japanese Unexamined Patent Application No.2003-296153. According to the technology disclosed in JapaneseUnexamined Patent Application No. 2000-293314, an unaccessed magneticdisk device is migrated to an energy-saving mode after a predeterminedtime has elapsed. According to the technology disclosed in JapaneseUnexamined Patent Application No. 2003-296153, at times of low load, adata storage position control device for a plurality of storage unitsredirects processing to another processing device, and migrates the CPUto a power-saving mode.

Each of the aforementioned magnetic disk device and CPU are devices thatparticipate in the processing of I/O commands received by a storagesystem (hereinafter I/O process-participating devices) from a hostdevice. There is possibility that storage system performance willdeteriorate as a result of an I/O process-participating device beingmigrated to a power-saving state.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to reduce thepower consumed by a storage system while suppressing deterioration ofthe storage system performance.

Additional objects of the present invention will become apparent fromthe description given herein.

If a load on one or more I/O process-participating devices or a partthereof of at least one type of storage unit, processor or cache memorywhich are I/O command processing-related I/O commandprocess-participating devices is a low load equal to or less than apredetermined threshold value, a state-related processing of the one ormore of the I/O process-participating devices or a part thereof isredirected to another one or more I/O process-participating devices or apart thereof, and the state of the one or more I/O process-participatingdevices or a part thereof is shifted to a power-saving state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a computer system configuration diagram pertaining to a firstembodiment of the present invention;

FIG. 2 is a hardware configuration diagram of a front-end (back-end)module of the first embodiment of the present invention;

FIG. 3 is a hardware configuration diagram of a processor module of thefirst embodiment of the present invention;

FIG. 4 is a hardware configuration diagram of a shared memory module ofthe first embodiment of the present invention;

FIG. 5 is a hardware configuration diagram of a service processor of thefirst embodiment of the present invention;

FIG. 6 is a hardware configuration diagram of a disk unit of the firstembodiment of the present invention;

FIG. 7 is a schematic diagram of the first embodiment of the presentinvention;

FIG. 8 is a diagram showing programs and various data of the firstembodiment of the present invention;

FIG. 9 is a diagram showing the configuration of processor moduleconfiguration information of the first embodiment of the presentinvention;

FIG. 10 is a diagram showing the configuration of processor modulenormal state information of the first embodiment of the presentinvention;

FIG. 11 is a diagram showing the configuration of processor informationof the first embodiment of the present invention;

FIG. 12 is a diagram showing the configuration of LDEV configurationinformation of the first embodiment of the present invention;

FIG. 13 is a diagram showing the configuration of a cache table of thefirst embodiment of the present invention;

FIG. 14 is a diagram showing the configuration of power managementinformation of the first embodiment of the present invention;

FIG. 15 is a diagram showing the configuration of routing information ofthe first embodiment of the present invention;

FIG. 16 is a flow chart of processor sleep control processing of thefirst embodiment of the present invention;

FIG. 17 is a flow chart of processor sleep method selection processingof the first embodiment of the present invention;

FIG. 18 is a flow chart of migratable processor module search processingof the first embodiment of the present invention;

FIG. 19 is a flow chart of I/O command process migration processing ofthe first embodiment of the present invention;

FIG. 20 is a flow chart of processor module high load processor startcontrol processing of the first embodiment of the present invention;

FIG. 21 is a flow chart of fault recovery processing of the firstembodiment of the present invention;

FIG. 22 is a schematic diagram of a second embodiment of the presentinvention;

FIG. 23 is a diagram showing programs and various data of the secondembodiment of the present invention;

FIG. 24 is a diagram showing the configuration of cache memory moduleinformation of the second embodiment of the present invention;

FIG. 25 is a diagram showing the configuration of memory blockinformation of the second embodiment of the present invention;

FIG. 26 is a flow chart of cache memory sleep control processing of thesecond embodiment of the present invention;

FIG. 27 is a flow chart of cache memory sleep processing of the secondembodiment of the present invention;

FIG. 28 is a flow chart of cache memory start control processing of thesecond embodiment of the present invention;

FIG. 29 is a schematic diagram of a third embodiment of the presentinvention;

FIG. 30 is a diagram showing programs and various data of the thirdembodiment of the present invention;

FIG. 31 is a diagram showing the configuration of LDEV state informationof the third embodiment of the present invention;

FIG. 32 is a diagram showing the configuration of RAID Group informationof the third embodiment of the present invention;

FIG. 33 is a diagram showing the configuration of power managementinformation of the third embodiment of the present invention;

FIG. 34 is a flow chart of disk sleep control processing of the thirdembodiment of the present invention;

FIG. 35 is a flow chart of LDEV migration destination search processingof the third embodiment of the present invention;

FIG. 36 is a flow chart of disk start control processing of the thirdembodiment of the present invention;

FIG. 37 is a configuration diagram of a computer system pertaining to afourth embodiment of the present invention;

FIG. 38 is a schematic diagram of the fourth embodiment of the presentinvention;

FIG. 39 is configuration diagram of a computer system pertaining to afifth embodiment of the present invention;

FIG. 40 is a schematic diagram of a fifth embodiment of the presentinvention;

FIG. 41 is a schematic diagram of a sixth embodiment of the presentinvention;

FIG. 42 is a schematic diagram of a seventh embodiment of the presentinvention; and

FIG. 43 is a diagram showing the configuration of a policy managementtable of the seventh embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In embodiment mode 1, a storage system comprises a plurality of storageunits on which a plurality of logical volumes are based, one or moreprocessors for writing data to a logical volume, of a plurality oflogical volumes, designated by an I/O command sent from a host device orreading data from this logical volume, and one or more cache memoriesfor temporarily storing data to be written in the logical volume by theprocessor or data read from the logical volume by the processor. Thestorage system comprises a power-saving controller. A power-savingcontroller redirects processing related to a state of one or more I/Oprocess-participating devices or a part thereof, for at least one ofstorage unit, processor and cache memory which are I/Oprocess-participating devices related to I/O command processing, toanother one or more I/O process-participating devices or a part thereof,and shifts the state of the one or more I/O process-participatingdevices or a part thereof to a power-saving state.

Here, the “power-saving state” refers to a state in which the powerconsumption of an I/O process-participating device or a part thereof isless than the power consumption thereof in its normal active state. Morespecifically, for example, a power supply OFF state constitutes a statein which the power source of an I/O process-participating device or apart thereof has been switched OFF. In addition, for example, if the I/Oprocess-participating device is used to drive a disk-type storage media,the power-saving state is taken as being a state in which the rotationspeed of this storage media is slower than the rotation speed thereof inits normal active state (state in which data read-write can occur).

In embodiment mode 2 according to embodiment mode 1, the processorsexist in plurality. The processors are constituent elements of theplurality of processor modules. The processor modules are configuredfrom one or more processors. The one or more I/O process-participatingdevices or a part thereof are processor modules or a part thereof. Thepart of the processor module is a processor, or at least one of aplurality of processor cores from which the processor is configured.

In embodiment mode 3 according to at least one of embodiment mode 1 orembodiment mode 2, the one or more logical volumes of the plurality oflogical volumes each are assigned to the processor modules. This storagesystem further comprises a host interface part. The host interface partreceives an I/O command sent from the host device and transfers this I/Ocommand to a processor module to which a logical volume designated bythis I/O command is assigned, of a plurality of processor modules. Apower-saving controller assigns the logical volume assigned to the lowload processor module of the plurality of processor modules to anotherprocessor module of the plurality of processor modules, thus shiftingthe state of this low load processor module to a power-saving state.

In embodiment mode 4 according to embodiment mode 3, a power-savingcontroller, when the load placed on the low load processor module isplaced on another processor module, judges whether or not the loadplaced on this other processor module exceeds a predetermined thresholdvalue, and assigns the logical volume assigned to the low load processormodule to the other processor module if the judged result thereofindicates that the load does not exceed the predetermined thresholdvalue.

In embodiment mode 5 according to at least one of embodiment modes 3 and4, a power-saving controller, if the load on the other processor moduleto which the logical volume has been assigned exceeds the predeterminedthreshold value, shifts the state of a power-saving state processormodule to a non-power-saving state, the logical volume being assignedfrom the other processor module to this processor module.

In embodiment mode 6 according to at least one of embodiment modes 2 to5, the plurality of processor modules are affiliated with two or morepower supplies. A power-saving controller judges whether or not, uponconversion of a state of a low load processor module to a power-savingstate, a non-power-saving state processor module will exist in singlepower supply alone, and shifts the state of the low load processormodule to a power-saving state if the judged result thereof indicatesthat the non-power-saving state processor module will exist in two ormore power supplies.

In embodiment mode 7 according to at least one of embodiment modes 2 to6, a power-saving controller judges whether or not, upon conversion of astate of a low load processor module to a power-saving state, only asingle non-power-saving state processor module is formed, and shifts thelow load processor module state to a power-saving state if the judgedresult thereof indicates that two or more non-power-saving stateprocessor modules exist.

In embodiment mode 8 according to embodiment mode 3, the processormodules each comprise a storage region in which I/O process controlinformation referenced by a processor during the I/O command process isstored. A power-saving controller stores the I/O process controlinformation stored in the storage region of the low load processormodule in the storage region of the other processor module, thusshifting the low load processor module state to a power-saving state.

In embodiment mode 9 according to at least one of embodiment modes 2 to8, a power-saving controller, if a plurality of non-power-saving stateprocessors exist in the low load processor module, shifts the state of aprocessor selected from these plurality of non-power-saving stateprocessors or a processor core selected from a plurality of processorcores from which the processor is configured to a power-saving statewhile not shifting the state of the processor module itself.

In embodiment mode 10 according to at least one of embodiment modes 2 to9, a power-saving controller, if the result of the judgment indicatesthat the performance is less than a predetermined performancerequirement upon conversion of a selected processor state to apower-saving state, shifts the state of a processor core selected from aplurality of processor cores from which the processor is configured to apower-saving state while not shifting the state of the aforementionedselected processor.

In embodiment mode 11 according to at least one of embodiment modes 2 to10, the storage system further comprises a storage region for storinginformation expressing an energy-saving level desired by a storageadministrator. In accordance with the energy-saving level indicated bythis information, a power-saving controller selects one of the processormodule, processor and processor core, as a target, for conversion to apower-saving state.

In embodiment mode 12 according to at least one of embodiment modes 1 to11, the cache memory is configured from a plurality of cache memoryregions. The one or more I/O process-participating devices or a partthereof are one or more cache memories, or at least one of the pluralityof cache memory regions from which the cache memory is configured.

In embodiment mode 13 according to embodiment mode 12, a power-savingcontroller, prior to shifting the state of the cache memory region to apower-saving state, evacuates the data stored in the cache memory regionto another non-power-saving state cache memory region or to at least oneof the plurality of storage units.

In embodiment mode 14 according to embodiment mode 13, RAID Groups areconfigured from two or more of the plurality of storage units, apower-saving controller being configured to be able to migrate alllogical volumes formed on the basis of a low load RAID Group to one ormore other RAID Groups, thus shifting the state of the storage unitsfrom which the low load RAID Group is configured to a power-savingstate. A power-saving controller, if evacuation of the data stored inthe cache memory region to a storage unit or migration of all logicalvolumes formed on the basis of a low load RAID Group to one or moreother RAID Groups is to occur simultaneously or substantiallysimultaneously, the power-saving controller implementing either theevacuation or migration processing first and initiating the otherprocessing subsequent to the completion of the first processing.

In embodiment mode 15 according to at least one of embodiment modes 1 to14, the RAID Groups are configured from two or more storage units of theplurality of storage units. A power-saving controller migrates alllogical volumes from which a low load RAID Group is formed to one ormore other low load RAID Groups, thus shifting the state of the storageunits from which this low load RAID Group is configured to apower-saving state.

In embodiment mode 16 according to embodiment mode 15, a power-savingcontroller judges whether or not, upon a load on a migration-targetedlogical volume being placed on another RAID Group, the load placed onthe other RAID Group exceeds a predetermined threshold value and, if thejudged result thereof indicates that the load does not exceed thepredetermined threshold value, migrates the migration-targeted logicalvolume based on the low load RAID Group to another RAID Group.

In embodiment mode 17 according to at least one of embodiment modes 1 to16, the storage system further comprises a storage region for storinginformation indicating a one or more I/O process-participating devicesor a part thereof desired by a storage administrator. A power-savingcontroller maintains even at low load the non-power-saving state of theI/O process-participating devices or a part thereof other than the oneor more I/O process-participating devices or a part thereof indicated bythis information.

In embodiment mode 18 according to at least one of embodiment modes 1 to17, the storage system further comprises a storage region for storinginformation indicating whether or not permission from a storageadministrator is required prior to conversion to a power-saving state.If the information indicates that the permission from a storageadministrator is required prior to conversion to a power-saving state, apower-saving controller outputs an inquiry as to whether a state of oneor more I/O process-participating devices or a part thereof may beshifted to a power-saving state prior to the state of one or more I/Oprocess-participating devices or a part thereof being shifted to apower-saving state, and if a reply to the effect that the state of oneor more I/O process-participating devices or a part thereof may beshifted to a power-saving state is input in response to this inquiry,shifts the state of one or more I/O process-participating devices or apart thereof to a power-saving state.

In embodiment mode 19 according to at least one of embodiment modes 1 to18, the I/O process-participating devices for which conversion to apower-saving state is possible are two or more types of processor, cachememory or storage unit. A threshold value that defines a low load of thevarious I/O process-participating devices constitutes a threshold valuewith which there is association with a policy value selected from aplurality of policy values.

In embodiment mode 20 according to at least one of embodiment modes 1 to19, a power-saving controller, when a load on a storage system or a partthereof is a low load equal to or less than a predetermined thresholdvalue, judges whether or not, upon conversion of the state of the one ormore I/O process-participating devices or a part thereof to apower-saving state, performance will be below performance inpredetermined requirements and, if the judged result thereof indicatesthat the performance will not be below the performance in predeterminedrequirements, shifts the state, at a low load, of one or more I/Oprocess-participating devices or a part thereof to a power-saving state.In other words, if the judged result thereof indicates that theperformance will be below the predetermined performance requirement, thestate of the low load one or more I/O process-participating devices or apart thereof is not shifted to a power-saving state.

The processings executed by the aforementioned power-saving controllermay be controlled by means of a management computer used to manage astorage system.

Two or more of the plurality of embodiments described above can becombined. In addition, each of the parts described above can beconstructed from either hardware or a computer program, or by acombination thereof (for example, part is actualized using a computerprogram and the remainder is actualized using hardware). The computerprogram is written into and executed by a predetermined processor. Inaddition, a storage region existing in a hardware resource such as amemory may be used for information processing based on a computerprogram written into and executed by a processor. In addition, thecomputer program may be installed in the computer through a storagemedium such as a CD-ROM, or it may be downloaded to a computer by way ofa communication network.

Embodiments of the present invention will be hereinafter described indetail with reference to the diagrams.

First Embodiment

To begin with, the configuration of computer system pertaining to afirst embodiment of the present invention will be described withreference to FIG. 1 to FIG. 6.

FIG. 1 is a diagram showing an exemplary configuration of a computersystem.

The computer system is configured from a storage system 100, one or morehosts 200, one or more management servers 300, a storage network 400 anda management network 500. The host 200 and storage system 100 areconnected by a Fibre Channel Interface with I/O command and datatransmission and reception being performed employing FCP (Fiber ChannelProtocol). In addition, the storage system 100 and management server 300are connected by Ethernet (Registered Trademark) with data transmissionand reception being performed using TCP/IP protocol.

There are no restrictions to the interface and protocol employed betweenthe storage system 100 and host 200. While this embodiment cites theemployment of Fibre Channel and FCP, Ethernet (Registered Trademark) andiSCSI or the like may also be used. Similarly, the Ethernet (RegisteredTrademark) and TCP/IP protocol used between the host 200 and themanagement server 300 is an illustrative example.

The host 200 is a computer in which data is stored in an LDEV (LogicalDEVice) supplied by the storage system 100. The “LDEV” referred to heredenotes a virtual storage region accessible by the host 200 using aLogical Address (“LDEV” can also be referred to as a “Logical Volume” ora “LU (Logical Unit))”. The host 200 transmits I/O commands containingLDEV identifying information to the storage system 100. As a result,data input/output commands are issued to the storage system 100. Forexample, when FCP is employed, the host 200 is able to specify the LDEV(the LDEV to serve as a data write destination or, alternatively, as adata read destination) on which data input/output is to be performed byappending to the I/O command, as LDEV identifier information, a numberknown as a LUN (Logical Unit Number). Examples of the informationcontained in an I/O command include information that indicates commandtype such as read or write, a Logical Address (for example, a LBA(Logical Block Address)) that denotes data storage position in the LDEV,and data transfer length.

The storage system 100 comprises a controller 1000, one or more diskunits 2000, a service processor 3000, and one or more power units 4000.The controller 1000 and disk unit 2000 perform datatransmission/reception employing Ultra SCSI Interface/Protocol. Inaddition, the controller 1000 and service processor 3000 are connectedby Ethernet (Registered Trademark) and perform datatransmission/reception using TCP/IP protocol. The power unit 4000supplies power to the controller 1000, disk unit 2000 and serviceprocessor 3000. This interface and protocol are illustrative examples.

The controller 1000 comprises one or more front-end modules 1200, one ormore processor modules 1100, one or more shared memory modules 1300, andone or more back-end modules 1600. The modules of the controller 1000are interconnected by an internal network 1700. The internal networkemploys Fiber Channel and FCP as its interface and protocol. Thisinterface and protocol are illustrative examples.

The processor module 1100 interprets the I/O command and issues acommand to the front-end module 1200 based on the interpreted result.Data transfer between the host 200 and shared memory module 1300 iscontrolled by the content of this command. In addition, the processormodule 1100 issues a command to the back-end module 1600 based on theinterpreted result of the I/O command. Data transfer between the sharedmemory module 1300 and disk unit 2000 is controlled by the content ofthis command. In addition, the processor module 1100 interprets alater-described management command and, based on this interpretedresult, controls the storage system 100 as a whole.

The front-end module 1200 receives an I/O command from the host 200 andtransfers this I/O command to the processor module 1100. In addition,the front-end module 1200 performs data transfer between the host 200and shared memory module 1300 in accordance with a command from theprocessor module 1100.

The back-end module 1600 performs data transfer between the sharedmemory module 1300 and the disk unit 2000 in accordance with a commandfrom the processor module 1100.

The shared memory module 1300 stores cache data. The “cache data”referred to here denotes data temporarily stored in a high-speed storagemedium. In addition, the shared memory module 1300 also storeslater-described control information related to the storage system 100.The front-end module 1200, the back-end module 1600 and the processormodule 1100 are accessible by the shared memory module 1300 by way ofthe internal network 1700.

The disk unit 2000 stores data to be written in the LDEV. The disk unit2000 is connected to the back-end module 1600.

A storage administrator uses the service processor 3000 to executevarious settings of the storage system 100. The service processor 3000connected to the processor module 1100 sends a later-describedmanagement command to the processor module 1100. In addition, thestorage administrator is able to operate the management server 300 toperform operations identical to the service processor 3000. Forsimplification of the description, the various settings performed usingthe management server 300 are hereinafter incorporated in the varioussettings performed using the service processor 3000.

The power unit 4000 supplies an externally-supplied power (for example,commercial power supply) to the devices of the storage system 100.Device groups to which power is supplied from the same power unit 4000are hereinafter referred to as the “power supplies”.

FIG. 2 is a diagram showing an exemplary hardware configuration of thefront-end module 1200 and back-end module 1600.

The front-end module 1200 is configured from at least one external I/F1210, a transfer control module 1220, a memory module 1230 and aprocessor 1240. In addition, the exemplary hardware configuration of theback-end module 1600 is identical to that of the front-end module 1200.

First, the front-end module 1200 will be described. The processor 1240executes various programs stored in the memory module 1230. The externalI/F 1210 transfers an I/O command received from the host 200 andperforms I/O data transmission/reception (data input/output accompanyingthe processing of I/O commands) in accordance with a command from theprocessor 1240. The transfer control module 1220 performs communicationand data transfer between the processor module 1100 and the sharedmemory module 1300 in accordance with a command from the processor 1240.Later-described various programs and data are stored in the memorymodule 1230. The power unit 4000 supplies power to these modules.

Next, the back-end module 1600 will be described. The processor 1240 toexecutes various programs stored in the memory module 1230. The externalI/F 1210 performs data access to the disk unit 2000 in accordance with acommand from the processor 1240. The transfer control module 1120performs communication and data transfer between the processor module1100 and the shared memory module 1300 in accordance with a command fromthe processor 1240. Later-described various programs and data are storedin the memory module 1230. The power unit 4000 supplies power to thesemodules.

FIG. 3 is a diagram showing an exemplary hardware configuration of theprocessor module 1100.

The processor module 1100 is configured from one or more processors1110, a transfer control module 1120 and a memory module 1130.

The processor 1110 executes various programs stored in the memory module1130. The transfer control module 1120 controls communication betweenanother processor 1110, the front-end module 1200, the back-end module1600, the shared memory module 1300 and the service processor 3000 inaccordance with a command from the processor 1110. Later-describedvarious programs and various data are stored in the memory module 1130.The power unit 4000 supplies power to these modules.

The processor 1110 comprises one or more internal cores 1111. The core1111 constitutes a calculation circuit possessed by the processor 1110,the greater the number of cores the better the processing capacity ofthe processor 1110. The power supply to one core 1111 can be controlledindependently of the power supply to another core 1111. In other words,a single core 1111 selected from among a plurality of cores 1111 can beput to sleep (migrated to a sleep state).

The processor module 1100 or processor 1110 comprises a function forbeing put to sleep based on either receipt of an external sleep commandor a self-executed sleep command. In addition, the processor module 1100or processor 1110 also comprises a function for being started based onreceipt of an external start command while sleeping (for example, aconfiguration in which at least an element for receiving an externalstart command (for example, a circuit) is put to sleep with the powersupply in the ON state).

The active processor module, active processor and active core describedhereinafter refer to a state in which a processor module, a processor,or a core is “active” (the active processor also includes a “core sleep”state of a processor). On the other hand, the sleeping processor module,sleeping processor and sleeping core refer to a state in which theprocessor module, processor or core are in the “sleep” state.

FIG. 4 is a diagram showing an exemplary hardware configuration of theshared memory module 1300.

The shared memory module 1300 is configured from a cache memory module1340, a control memory module 1320 and a memory controller 1310.

The cache memory module 1340 constitutes, for example, a volatile memoryaccessible at higher speed than a hard disk drive (HDD). A portion ofthe data stored in the disk unit 2000 is temporarily stored in the cachememory module 1340 as cache data. Later-described control informationrelated to the storage system 100 is stored in the control memory module1320. The memory controller 1310 performs data transmission/receptionbetween these two memory modules and the front-end module 1200, theprocessor module 1100 and the disk unit 2000. The power unit 4000supplies power to these modules.

In addition, the control memory module 1320 comprises a lock mechanism.The “lock mechanism” referred to here denotes a synchronizing mechanismby which access of one subject to a resource being used by anothersubject is restricted. In order for the processor 1110 to access thecontrol memory module 1320 the lock must be acquired.

The cache memory module 1340 comprises a function for putting a part ofthe region of the cache memory module 1340 as a whole to sleep based onreceipt of an external sleep command. In addition, the cache memorymodule 1340 also comprises a function by which it is restarted based onreceipt of an external start command while sleeping (for example, aconfiguration in which at least an element for receiving an externalstart command (for example, a circuit) is put to sleep, for the entiretyof the cache memory module 1340, with the power supply in the ON state).

FIG. 5 is a diagram showing an exemplary hardware configuration of theservice processor 3000.

The service processor 3000 is configured from one or more processors3010, a memory module 3030, a transfer control module 3020 and a display3040. The processor 3010 executes a management I/F program stored in thememory module 3030. The management I/F program is stored in the memorymodule 3030. The transfer control module 3020 controls communicationwith the processor module 1100 in accordance with a command from theprocessor 3010. The power unit 4000 supplies power to these modules.

FIG. 6 is a diagram showing an exemplary hardware configuration of adisk unit 2000.

One or more disks 2010 are housed in the disk unit 2000. The disk unit2000 is configured from a RAID (Redundant Array of Inexpensive Disks)based on the assembly of a plurality of disks 2010. RAID refers to atechnology based on the assembly of a plurality of storage units thathas application as a virtual single hard disk. An accumulation of disks2010 from which a RAID is configured is known as a “RAID Group”. Inaddition, a LDEV is formed in accordance with the storage space providedby a RAID Group and is defined on the basis of a RAID Groupconfiguration. A plurality of LDEV can be formed in accordance with thestorage space of a single RAID Group. The power unit 4000 supplies powerto the disks 2010.

There are no restrictions to the method for configuring a LDEV. Whilethis embodiment cites an example of a method for defining a plurality ofLDEV with respect to a single RAID Group, a single LDEV may be definedwith respect to a single RAID Group and a plurality of LDEV may bedefined with respect to a plurality of RAID Groups.

In addition, while the disk 2010 constitutes, for example, a HDD (HardDisk Drive), other types of disk drive (for example, optical disk drive)may also be used. In addition, instead of a disk drive, other types ofstorage units (for example, a semiconductor memory drive such as a flashmemory) may be adopted.

Next, an overview of the first embodiment will be described withreference to FIG. 7.

In the first embodiment, the power consumption of the processor module1100 is reduced.

The I/O command process executed by the processor module 1100 will behereinafter briefly described. The following description assumes thatthe LDEV the plurality of LDEV that is to be managed has been assignedto the processor module 1100.

The front-end module 1200 receives an I/O command from the host 200 andtransfers this I/O command to, of the one or more processor modules1100, the managing processor module 1100 of the LDEV designated by theI/O command. The managing processor module 1100 interprets the I/Ocommand received from the front-end module 1200 and, based on thisinterpreted result, executes write and read to the I/O data cache memorymodule 1340, as well as data write to the disk unit 2000 or data readfrom the disk unit 2000.

In this kind of I/O command process, the processor module 1100 executesa large number of processings including I/O command interpreting, I/Odata writing, and logical to physical address conversion and, as aresult, performance bottlenecks in the processor module 1100 are liableto occur. As a method for suppressing performance deterioration, amethod based on increasing the number of processor modules 1100 mountedin the storage system 100 has been considered. However, increasing thenumber of processor modules 1100 results in increased power consumptionby the processor modules 1100.

Thereupon, in this first embodiment, a low load processor module 1100migrates the I/O command process to a redundant performance processormodule (processor module in which, even though the load is increased tosome extent, the load is not high) 1100, and then goes to sleep. As aresult, the power consumption of the storage system 100 can be reduced.

More specifically, the power consumption is reduced as a result of, forexample, the low load processor module 1100 putting the processor 1110of this module 1100 or the core 1111 of the processor 1110 to sleep. Inaddition, even when a single active processor 1110 alone exists and theload state is even lower, the low load processor module 1100 migratesthe I/O command process of the managed LDEV (LDEV which the low loadprocessor module 1100 is managing) to a performance redundant processormodule 1100 and itself goes to sleep. As an example of load evaluationcriteria, the ratio of the maximum number of I/O command processings(maximum number of processable I/O commands) per unit time (for example,per second) to current number of I/O commands is employed in thisembodiment. In addition to this, load can be evaluated on the basis ofthe number of I/O commands received per unit time, or on the basis ofthe load and temperature and so on of a processor 1110 indicated bymonitored information.

Consideration of this process raises the additional problems 1 to 4noted below.

(Problem 1) There is a concern that, as a result of the processor module1100 going to sleep, the active processor module 1100 will exist in asingle power supply alone. This being the case, a fault occurring in thepower supply to the active processor module 1100 will result in theabsence of a processor module 1100 capable of processing I/O commandsand will lead in turn to a temporary system-down state.

(Problem 2) There is a concern that, subsequent to the processor module1100 going to sleep, a drop in the processor processing capacity of thestorage system 100 as a whole will occur and, in turn, the LDEVperformance requirement will not be met. The “LDEV performancerequirement” referred to here denotes the number of I/O commands withrespect to the LDEV that the storage system 100 must process per unittime (for example, per second). The LVED performance requirement can beset by a storage administrator.

(Problem 3) There is a problem inherent to the I/O command process beingmigrated to a different processor module 1100 in that the memory module1130 of the migration source processor module 1100 cannot be referred toat the migration destination. For example, the processor module 1100utilizes a later-described LDEV configuration information copy 1135 orcache table copy 1136 of the memory module 1130 to increase the speed ofthe I/O command process. However, new information related to the LDEVbeing managed does not exist in the memory module 1130 of the processormodule 1100 to which the I/O command has been migrated. Accordingly,upon receipt of the I/O command at the migrated LDEV, the migrationdestination processor module 1100 must examine this information by wayof the control memory module 1320 and, accordingly, response speeddrops.

(Problem 4) When a storage administrator wishes to emphasize performanceover the amount of power reduction, a trade-off between powerconsumption reduction amount and performance and fault tolerance cannotbe set.

The following means 1 to 4 are implemented in this first embodiment toresolve these problems.

(Means 1) The low load processor module 1100, prior to going to sleep,judges whether or not another processor module 1100 is being activatedby two or more power supplies, and goes to sleep if the adjudged resultthereof provides indication to that effect. As a result, in the storagesystem 100, the existence of processor modules 1100 activated by two ormore power supplies is always guaranteed. Accordingly, a system-downstate due to occurrence of power supply fault can be prevented. Whilethe number of power supplies in which the active processor module 1100exists is confirmed in this (Means 1), the number of active processormodules 1100 may instead be confirmed. That is, the low load processormodule 1100, prior to going to sleep, judges whether or not two or moreother active processor modules 1100 exist, and goes to sleep if theadjudged result thereof provides indication to that effect. As a result,if a fault occurs in any of the other active processor modules 1100, asystem-down state can be prevented.

(Means 2) The low load processor module 1100 judges whether or not, whenthe load placed thereon is to be migrated to another processor module1100, the LDEV performance requirement will be met, and whether the loadon the other processor module 1100 will be high or not. If the LDEVperformance requirement will be met and the load on the other processormodule 1100 will not be high, the low load processor module 1100 assignsthe managed LDEV assigned thereto to the other processor module 1100 andgoes to sleep. As a result, when the managed LDEV assigned to the lowload processor module 1100 is assigned to the migration destinationprocessor module 1100, the LDEV performance requirement can be met.

(Means 3) The low load processor module 1110, prior to migration of theI/O command process, issues a command to the migration processor module1100 to produce the LDEV configuration information copy 1135 and cachetable copy 1136 in the memory module 1130. Accordingly, when the I/Ocommand process is migrated between different processor modules 1100, adrop in response performance of the storage system 100 can prevented.

(Means 4) An energy-saving power level, low load threshold value andhigh load threshold value are received from the service processor 3000by at least a processor module 1100 which writes the receivedenergy-saving power level, low load threshold value and high loadthreshold value in the shared memory module 1300. The processor module1110 executes processing on the basis of this energy-saving power level,low load threshold value and high load threshold value. As a result, atrade-off between power consumption amount reduction and performance andfault tolerance can be set.

The “energy-saving power level” referred to here denotes a sleep methodby which processor sleep, processor module sleep and core sleep areenabled. In this embodiment, the energy-saving power level is settablefrom level 1 to level 4. When level 1 is set, the processor module 1100does not execute power management. When level 2 is set, the processormodule 1100 is able to execute core sleep. When level 3 is set, theprocessor module 1100 is able to execute core sleep and processor sleep.When level 4 is set, the processor module 1100 is able to executeprocessor sleep, processor module sleep and core sleep.

The “processor module sleep” referred to here denotes a state in whicheach of a processor 1110, memory module 1130 and transfer control module1150 of the processor module 1100 are sleeping. The “processor sleep”denotes when a processor 1110 alone is sleeping. The “core sleep”denotes when a core 1111 is sleeping.

Each of the aforementioned problems 1 to 4 can be resolved by thesemeans 1 to 4. The first embodiment will be hereinafter described indetail.

The various programs and various data of the storage system 100 will bedescribed with reference to FIG. 8.

The front-end module 1200 performs FE data transfer processing based onexecution of an FE (Front End) data transfer program 1232 stored in thememory module 1230 by the processor 1240.

A processor module 1100 performs each of an I/O command process, astorage management processing, a power management processing and a faultrecovery processing based on an I/O command process program 1131,storage management program 1132, power management program 1133 and faultrecovery program 1134 stored in the memory module 1130 being executed bythe processor 1110.

The back-end module 1600 performs BE data transfer processing based onexecution of a BE data transfer program 1601 by the processor 1240.

The service processor 3000 performs management I/F processing based on amanagement interface (I/F) program 3031 stored in a memory module 3030being executed by the processor 3010.

The processings performed on the basis of execution of each of the FEdata transfer program 1232, I/O command process program 1131, storagemanagement program 1132, power management program 1133, fault recoveryprogram 1134, BE data transfer program 1601 and management I/F program3031 by the respective processors (for example, microprocessors) mayalso be actualized using, for example, integrated circuit-basedhardware. For the purpose of simplification of the description, theprocessings actualized as a result of execution of the programs by theprocessor 1110, processor 1240 and processor 3010 are referred to in thedescription as the subject.

The FE data transfer program 1232 transfers an I/O command received froma host 200 to a processor module 1100 correspondent to an LUN containedin this I/O command. In addition, the FE data transfer program 1232controls data transfer between the host 200 and storage system 100 inaccordance with a command from the processor module 1100. The routinginformation 1231 indicates the managing processor module 1100 of eachLUN. The particulars of the routing information 1231 are described laterwith reference to FIG. 15.

The BE data transfer program 1601 controls data transfer between thecontroller 1000 and disk unit 2000 in accordance with a command from theprocessor module 1100.

The LDEV configuration information copy 1135 stored in the memory module1120 of the processor module 1100 constitutes a copy of all or a portionof a later-described LDEV configuration information 1325. The processormodule 1100 performs high-speed processing (for example, conversion fromlogical to physical address) based on reference to the LDEVconfiguration information copy 1135 and not the LDEV configurationinformation 1325 stored in the shared memory module 1300.

The cache table copy 1136 stored in the memory module 1120 of theprocessor module 1100 constitutes a copy of a portion of an LDEV managedby a later-described cache table 1327. By reference to the cache tablecopy 1136, the processor module 1100 can assess at high speed whether ornot LDEV data exists in the cache data 1341.

The I/O command process program 1131 executed by the processor module1100 interprets the I/O command transferred from the front-end module1200 and performs a processing designated by a command code.

If data read is designated by the command code, the I/O command processprogram 1131 first reads the LUN, address and the transfer length of theI/O command. Next, the I/O command process program 1131, referring tothe cache table copy 1136, examines whether or not the data in question(data that should be read in accordance with an I/O command) exists inthe cache data 1341 of the cache memory module 1340. If cache dataexists, the I/O command process program 1131 issues a command to the FEdata transfer program 1232 to transfer this cache data 1341 to the host200.

If this cache data does not exist, the I/O command process program 1131issues a command to the BE data transfer program 1601 to perform a datatransfer from the disk unit 2000 to the cache memory module 1230. If thecache data exists, the I/O command process program 1131 then issues acommand to the FE data transfer program 1232 to transfer the cache data1341 to the host 200. Finally, the I/O command process program 1131updates the cache table 1327 and the cache table copy 1136.

If data write is designated by the command code, the I/O command processprogram 1131 first reads the LUN, the address and the transfer length ofthe I/O command. Next, the I/O command process program 1131 issues acommand to the FE data transfer program 1232 to perform a transfer ofdata from the host 200 to the cache memory module 1340. Subsequent tothe completion of this data transfer, the I/O command process program1131 transmits an END message to the host 200. The I/O command processprogram 1131 then updates the cache table 1327 and the cache table copy1136.

In addition, the I/O command process program 1131 regularly (orirregularly) confirms the contents of the cache table 1327 and examinesthe volume of unwritten data in the disk unit 2000. When the unwrittendata exceeds a fixed volume, the I/O command process program 1131 issuesa command to the back-end module 1600 to destage the cache data 1341.The “destage” referred to here denotes writing of unwritten cache datain the disk unit 2000. The I/O command process program 1131 thenaccesses the cache table 1327 and updates a write flag correspondent toa memory block (constituent element of the cache memory module 1340) inwhich the destaged cache data exists from “unwritten” to “written”.

The storage management program 1132 receives a management command fromthe service processor 3000 and updates the various control informationstored in the control memory module 1320 in accordance with thismanagement command. Examples of this control information includeprocessor module configuration information 1321, processor module stateinformation 1322, processor information 1324, LDEV configurationinformation 1325 and power management information 1326. The LDEVconfiguration information copy 1135 is updated simultaneously with theupdate of the LDEV configuration information 1325.

The power management program 1133 monitors the active state of theprocessor 1110 and regularly (or irregularly) updates the processorinformation 1324 and processor module state information 1322 stored inthe control memory module 1320. In addition, the power managementprogram 1133 regularly (or irregularly) executes a processor sleepcontrol. The particulars of the processor sleep control are describedlater with reference to FIG. 16 to FIG. 19. In addition, the powermanagement program 1133 regularly (or irregularly) executes theprocessor start control described by FIG. 20 of a sleeping processormodule 1100, sleep processor 1110 or sleeping core 1111, and starts thesleeping processor module 1100, sleep processor 1110 or sleeping core1111 when the load on the processor module 1100 is high. However, whenlevel 1 is indicated by the later-described power management information1326 input by way of the service processor 3000 by a storageadministrator and stored in the shared memory module 1300, the powermanagement processing described above is not executed by the processormodule 1100.

The fault recovery program 1134, upon detection of fault in aself-executing processor module 1100, notifies one of the other activeprocessor modules 1100 of fault generation. In addition, the faultrecovery program 1134 regularly (or irregularly) sends a heartbeatsignal to another active processor module 1100. The “heartbeat signal”referred to here denotes an externally-sent signal used to providenotification that the program itself is being activated normally. Whennotification of a fault from another processor module 1100 is providedor receipt of the heartbeat signal is interrupted, the fault recoveryprogram 1134 executes the fault recovery of the processor module 1100 inquestion. The particulars related to the actuation of the fault recoveryprogram 1134 during execution of processor fault recovery will bedescribed later with reference to FIG. 21.

The various control information stored in the control memory module 1320will be described later with reference to FIG. 9 to FIG. 14.

The cache data 1341 is divided into a plurality of data blocks that arestored in respectively different LDEV. The “data blocks” referred tohere denote cache data 1341 management units. Referring to FIG. 14, thelater-described cache table 1327 retains a correspondence relationshipbetween these data blocks and LDEV addresses.

The management I/F program 3031 displays a management screen (forexample, GUI (Graphical User Interface)) on a display 3040. The storageadministrator sets the LDEV performance requirement and inputs theenergy-saving power level, low load threshold value and high loadthreshold values of the processor module 1100 by way of this managementscreen. The I/F program 3031 transmits the information input by thestorage administrator as a management command to the processor module1100 on which the storage management is being performed.

The processor module configuration information 1321, processor modulestate information 1322, processor information 1324, LDEV configurationinformation 1325, power management information 1326 and cache table 1327stored in the control memory module 1320 will be described withreference to FIG. 9 to FIG. 14. This information includes informationsuch as the configuration of the hardware and LDEV and so on, thesettings established by the storage administrator, and deviceperformance and active conditions such as the number of accesses fromthe host.

FIG. 9 shows the configuration of the processor module configurationinformation 1321.

The processor module configuration information 1321 which is providedas, for example, a table, contains information related to theconfiguration and setting of the processor module 1100. The processormodule configuration information 1321 comprises an entry region 1321 ato entry region 1321 g for each processor module 1100.

More specifically, a processor module 1100 identifying number (processormodule number) of the is stored in the entry region 1321 a. Anidentifying number of the processor 1110 (processor number) of theprocessor module 1100 of the entry is stored in the region 1321 b. Anidentifying number of the LDEV managed by a processor module 1100(managed LDEV number) is stored in the entry region 1321 c. Anidentifying number of the LDEV initially managed by a processor module1100 (initially managed LDEV number) is stored in the entry region 1321d. A threshold value (low load threshold value) serving as a referencefor determining whether or not the processor module 1100 is a low loadis stored in the entry region 1321 e. The threshold value (high loadthreshold value) serving as a reference for determining whether or notthe processor module 1100 is a high load is stored in the entry region1321 f. A identifying number of the power supply (power supply number)to which a processor module 1100 is affiliated is stored in the entryregion 1321 g.

The processor module in which a processor exists can be specified byreference to this processor module configuration information 1321.

FIG. 10 shows the configuration of the processor module stateinformation 1322.

The processor module state information 1322 which is provided as, forexample, a table, contains information related to the performance andactive conditions of a processor module 1100. The processor module stateinformation 1322 comprises an entry region 1322 a to entry region 1322 efor each processor module 1100.

A processor module 1100 identifying number (processor module number) isstored in the entry region 1322 a. The sum total of the capacityperformance of the active processor modules 1100 of a processor 1110(processor module capacity performance) is stored in the entry region1322 b. The capacity performance of a processor 1110 referred to heredenotes the number of I/O commands processable thereby per unit time(for example, per second). This capacity performance changes inaccordance with the number of active cores in an active processor 1110.The I/O command number that must be processed by the processor module1100 per unit time (processor module performance requirement) in orderto meet the performance requirement of the LDEV being managed is storedin the entry region 1322 c. Accordingly, the value stored in the entryregion 1322 c constitute a sum total of the performance requirements ofthe LDEV being managed by the processor modules 1100 (the LDEVperformance requirements are stored in the LDEV configurationinformation table of FIG. 12). A current processor module 1100 load isstored in the entry region 1322 d. The stored load constitutes a value(for example, a percentage of processor module capacity performance withrespect to processor module current performance) calculated on the basisof the processor module capacity performance stored in the entry region1322 b and the number of I/O commands processed by the current processormodule 1100 (hereinafter processor module current performance).Information (processor module state) that expresses the state of aprocessor module 1100 such as “active”, “sleep” or “fault” is stored inthe entry region 1322 e.

FIG. 11 shows the configuration of the processor information 1324.

The processor information 1324 which is provided as, for example, atable, contains information related to the performance, configurationand operational state of a processor 1110. The processor information1324 comprises an entry region 1324 a to entry region 1324 e for eachprocessor 1110.

A processor 1110 identifying number (processor number) is stored in theentry region 1324 a. A capacity performance (core capacity performance)of each core of a processor 1110 is stored in the entry region 1324 b.The number of current active cores (active core number) is stored in theentry region 1324 c. The performance (processor capacity performance) ofa processor 1110 is the product of core capacity performance and numberof active cores. The number of I/O commands per second processed by thecurrent processor 1110 (processor current performance) is stored in theentry region 1324 d. Information (processor state) expressing the stateof the processor 1110 such as “active”, “sleep”, “core sleep” is storedin the entry region 1324 e.

The core capacity performance value may be a value input by either anadministrator or storage administrator of the storage system 100, or itmay be a value automatically calculated by a processor module 1100 fromoperation results or device specifications.

FIG. 12 shows the configuration of the LDEV configuration information1325.

The LDEV configuration information 1325 which is provided as, forexample, a table, contains information related to the configuration andsetting of LDEV. The LDEV configuration information 1325 comprises anentry region 1325 a to entry region 1325 f for each LDEV.

A LDEV identifying number (LDEV number) is stored in the entry region1325 a. An identifying number of the RAID Group defined by LDEV (RAIDGroup number) is stored in the entry region 1325 b. The head physicaladdress (initial address) of the RAID Group of the LDEV is stored in theentry region 1325 c. The LDEV storage capacity (region size) assigned tothe RAID Group is stored in the entry region 1325 d. In the example ofthis embodiment, megabyte is employed as the unit of region size. A portidentifier-LUN set correspondent to an LDEV is stored in the entryregion 1325 e. The LDEV performance requirement established by a storageadministrator is stored in the entry region 1325 f.

FIG. 13 shows the configuration of the cache table 1327.

The cache table 1327 contains information related to cache data 1341storage position. The cache table 1327 comprises an entry region 1327 ato entry region 1327 e for each data block (LDEV constituent element).

A identifying number (LDEV number) of an LDEV comprising a data block isstored in the entry region 1327 a. A head logical address havingcorrespondence to a data block is stored in the entry region 1327 b.Data size (stored data length) stored in the data block is stored in theentry region 1327 c. A physical address of a memory block of a cachememory module having correspondence to a data block is stored in theentry region 1327 d. Information related to whether or not data storedin a memory block is already written in a corresponding data block (forexample, information as to whether it is “written” or “unwritten”) isstored in the entry region 1327 e.

FIG. 14 schematically shows the configuration of the power managementinformation 1326.

The power management information 1326 contains information related topower management-related settings. The power management information 1326comprises an entry region 1326 a, and values expressing theaforementioned energy-saving power level are stored in this entry region1326 a.

FIG. 15 shows the configuration of the routing information 1231 storedin the front-end module 1200.

The routing information 1231 contains the correspondence relationshipbetween a LUN and a processor module that manages the LDEV correspondentto the LUN. The routing information 1231 which is provided as, forexample, a table, comprises an entry region 1231 a and an entry region1231 b for each LUN.

LUN are stored in the entry region 1231 a. A identifying number of aprocessor module 1100 managing the LDEV (managing processor modulenumber) correspondent to the LUN is stored in the entry region 1231 b.

Next, the various processings executed by this embodiment will bedescribed with reference to FIG. 16 to FIG. 21. The steps of thesediagrams enclosed by a double line will be described in detail withreference to other diagrams.

FIG. 16 is a flow chart of processor sleep control processing. The stepsthereof will be hereinafter described. For convenience of thedescription, a single processor module serving as a target of processingwill be hereinafter referred to as the “target processor module”.

(S100) The power management program 1133 reads the processor moduleconfiguration information 1321, processor module state information 1322,processor information 1324 and power management information 1326 fromthe control memory module 1320.

(S101) The power management program 1133 calculates the product of thecore capacity performance (in other words, the processor capacityperformance) of the processor information 1324 (information stored inthe entry region 1324 b) and the number of active cores (informationstored in the entry region 1324 c) of the active processors 1110 of atarget processor module (in other words, self-actuating processormodule) 1100. In addition, the power management program 1133 calculatesthe sum total of the processor capacity performance of the one or moreactive processors (processors correspondent to the “active” processorstate) existing in the target processor module 1100, in other words, theprocessor module capacity performance, and stores the calculatedprocessor module capacity performance in the entry region 1322 b.Furthermore, the power management program 1133 examines the processorcurrent performance of the active processors (the number of I/O commandsprocessed per second which is information stored in the entry region1324 d). The power management program 1133 calculates the processormodule load from the sum total of the processor current performance ofthe active processors and the aforementioned processor module capacityperformance, and stores this calculated processor module load in theentry region 1322 d.

(S102) The power management program 1133 compares the processor moduleload obtained in S101 with a low load threshold value (informationstored in the entry region 1321 e) correspondent to the target processormodule 1100 executing S103 when the processor module load is less thanthe low load threshold value, and otherwise ending the processor sleepcontrol.

(S103) The power management program 1133 selects a sleep method inresponse to the energy-saving power level (energy-saving power levelindicated by the power management information 1326) set by a storageadministrator. The particulars of sleep method selection will bedescribed later with reference to FIG. 17. If processor module sleep isselected, the power management program 1133 also executes an I/O commandprocess migration destination processor module 1100 search.

(S104) If processor module sleep is selected in S103 the powermanagement program 1133 executes S105. Otherwise, it executes S106.

(S105) The power management program 1133 migrates the I/O commandprocess of the LDEV managed by a self-executing processor module 1100 tothe migration destination processor module 1100 found in S103. Theparticulars of the I/O command process migration will be described laterwith reference to FIG. 19.

(S106) If processor module sleep is selected in S103, the powermanagement program 1133 updates information stored in the entry region1322 e correspondent to the target processor module 1100 to “sleep”. Ifprocessor sleep is selected in S103, the power management program 1133updates the information stored in the entry region 1324 e correspondentto the selected processor 1110 (processor 1110 selected in the S410processing of FIG. 17) processing to “sleep”. If core sleep is selectedin S103, the power management program 1133 updates the informationstored in the entry region 1324 e correspondent to the selectedprocessor 1110 (core 1111 selected in the S420 processing of FIG. 17) to“core sleep” and, furthermore, in order to put a single core 1111 tosleep, decreases the number of active cores stored in the entry region1324 c correspondent to the selected processor 1110 by one (for example,where the number of active cores is N, updates this to N−1).

Thereafter, the power management program 1133 puts the processor 1110,processor module 1100 or core 1111 to sleep in response to the selectedsleep method. However, when no sleep method is selected, the powermanagement program 1133 is not executed.

During this series of processings, the power management program 1133acquires the control memory module 1320 lock and prohibits access to thecontrol memory module 1320 by another power management program 1133.

FIG. 17 is a flow chart of processor sleep method selection processing.

(S400) The power management program 1133 examines the energy-savingpower level (entry region 1326 a) indicated by the power managementinformation 1326 executing S401 if the energy-saving power level is 4,S410 if the energy-saving power level is 3, and S420 if theenergy-saving power level is 2.

(S401) The power management program 1133 examines on the basis of theprocessor number (entry region 1321 b) of the processor moduleconfiguration information 1321 and the processor state (entry region1324 e) of the processor information 1324 if one or two or more targetprocessor modules 1100 exist in the active processor 1110. The powermanagement program 1133 executes S402 if there is one in the activeprocessor 1110, and otherwise executes S410.

(S402) The power management program 1133 searches for a migrationdestination processor module 1100. The particulars of the migrationdestination processor module search processing will be described laterwith reference to FIG. 18.

(S403) If the migration destination processor module 1100 is found inS402, the power management program 1133 executes S404, while otherwisethe power management program 1133 executes S420.

(S404) The power management program 1133 selects processor module sleepand ends the sleep method selection processing.

(S410) The power management program 1133 selects a single processor 1110from the one or more active processors in the target processor module1100 and calculates the current performance of the processor module 1100subsequent to the selected processor 1110 being put to sleep. Thiscurrent performance is calculated by, for example, subtraction of thecurrent performance of the selected processor from the currentperformance of the target processor module. The power management program1133 executes S411 when the calculated current performance is greaterthan the processor module performance requirement (value stored in theentry region 1322 c), and otherwise executes S420.

(S411) The power management program 1133 selects the processor sleep andends the sleep method selection processing.

(S420) The power management program 1133 selects one (or a plurality) ofcores from two or more active cores of an active processor andcalculates the capacity performance of the processor module 1100subsequent to the selected core 1111 being put to sleep. This capacityperformance is calculated by, for example, subtracting the capacityperformance of the selected core from the capacity performance of thetarget processor module. The power management program 1133 executes S421when the calculated capacity performance is greater than the processormodule performance requirement (value stored in the entry region 1322c), and otherwise ends the sleep method selection processing without asleep method having been selected.

(S421) The power management program 1133 selects core sleep and ends thesleep method selection processing.

FIG. 18 is a flow chart of the migration destination processor modulesearch processing.

(S300) The power management program 1133, referring to the processormodule state information 1322, judges whether or not two or moreprocessor modules 1100 other than the target processor module 1100 areactive using two or more power supplies. The power management program1133 executes S301 if this is the case, and otherwise ends theprocessing.

(S301) The power management program 1133 selects one of the other activeprocessor modules 1100 as an assessment target for whether or notmigration is possible.

(S302) The power management program 1133, referring to the processormodule state information 1322, specifies the capacity performance andload of a self-actuating target processor module 1100 and capacityperformance and load of the assessment target processor module 1110. Thepower management program 1133 calculates a capacity performance ratio oftwo processor modules 1100 (capacity performance of target processormodule/capacity performance of assessment target processor module), andcalculates the product of the target processor module 1100 load and thecalculated capacity performance ratio noted above (in other words, aload increase estimate of the assessment target processor module 1100).The power management program 1133 then calculates the sum of this loadincrease estimate and the assessment target processor module 1100 load(in other words, the load estimate following migration). When the loadestimate following migration is less than the high load threshold valueof the assessment target processor module 1100 (value stored in theentry region 1321 f), the power management program 1133 executes S303.Otherwise, the power management program 1133 ends the assessment of thecurrent assessment target processor 1110 and executes S305.

(S303) The power management program 1133 calculates the sum of theperformance requirement of the target processor module (in other words,the migration destination processor module) 1110 and the performancerequirement of the assessment target processor module (in other words,the performance requirement following migration of the assessment targetprocessor module). The power management program 1133 compares thecapacity performance and performance requirement following migration ofthe assessment target processor module 1100. The power managementprogram 1133 executes S304 when the performance requirement followingmigration is equal to or less than the capacity performance of theassessment target processor module 1100, and otherwise the powermanagement program 1133 ends the appraisal of the current assessmenttarget processor 1110 and executes S305.

(S304) The power management program 1133 appends the assessment targetprocessor module 1100 to the search result (for example, stores theprocessor module number of the assessment target processor module 1100to predetermined electronic information temporarily prepared in thememory module 1130).

(S305) When all active processor modules 1100 have been assessed thepower management program 1133 end this search processing. Otherwise, thepower management program 1133 executes S300.

FIG. 19 is a flow chart of I/O command process migration processing.

(S500) The power management program 1133 reads the LDEV managed by atarget processor module 1100 (entry region 1321 c) from the processormodule configuration information 1321 and appends this to the LDEVmanaged by a migration destination processor module 1100 (entry region1321 c). At this time, the power management program 1133 updatesinformation stored in the entry region 1322 e correspondent with atarget processor module 1110 to “sleep”. In addition, the powermanagement program 1133 updates information stored in the entry region1324 e correspondent to the processors 1110 existing in the targetprocessor module to “sleep”.

(S501) The power management program 1133 sends a memory module updatemessage to the migration processor module 1100 issuing a command toperform memory module update. The memory module update message containsthe LDEV number managed by the self-actuating processor module 1100. Thepower management program 1133 of the migration destination processormodule 1100 that has received this messages appends information from thecache table 1327 of the shared memory module 1300 related to the LDEV tobe migrated to the cache table copy 1136. The power management program1133 of the migration destination processor module 1100 similarlyupdates the LDEV configuration information copy 1135. In addition, thepower management program 1133 of the migration destination processormodule 1100 appends the LDEV performance requirement (entry region 1325f) to the value of the processor module performance requirement (entryregion 1322 c). Following completion of these processings, the migrationpower management program 1133 sends and END message to the migrationdestination processor module 1100.

(S502) Following receipt of the END message of S501, the powermanagement program 1133 examines the LDEV managed by the self-actuatingprocessor module 1110 of the LDEV configuration information copy 1135.Thereupon, the power management program 1133 sends a routing alterationmessage to the front-end module 1200 issuing a command for alteration ofthe I/O command routing. The routing alteration message contains the LUNof the LDEV to be migrated and the number of the migration destinationprocessor module 1100. The FE data transfer program 1232 of thefront-end module 1200 designated to perform the routing alterationupdates the number of the processor module managing the LUN indicated inthe routing alteration message to the number of the migrationdestination processor module 1110. The FE data transfer program 1232then sends and END message to the power management program 1133. Inaddition, the FE data transfer program 1232 transfers an I/O command ofa subsequent migration source processor 1110 to a migration destinationprocessor 1110. The power management program 1133, subsequent toreceiving the END message, ends the I/O process migration.

FIG. 20 is a flow chart of a processor start control processing executedwhen the load on the migration destination processor module is high.

(S600) The power management program 1133 executed by the migrationdestination processor module of FIG. 19 calculates the load on theprocessor module 1100 using the method described in S101 of FIG. 16.

(S601) When the load obtained in S600 is equal to or greater than thehigh (CPU) load threshold value (entry region 1321 f) correspondent tothe processor module 1100 thereof the power management program 1133executes S602, and otherwise ends the processor start control.

(S602) The power management program 1133, referring to the processorinformation 1324, examines whether or not a core sleep processor 1110exists in the processor module 1100. When no sleeping core exists, thepower management program 1133 executes S603, and otherwise executesS610.

(S603) The power management program 1133, referring to the processorinformation 1324, examines whether or not a sleep processor 1110 existsin this processor module. When no sleeping processor exists, the powermanagement program 1133 executes S604, and otherwise executes S620.

(S604) The power management program 1133 examines, on the basis of themanaged LDEV (entry region 1321 c) and the initial managed LDEV (entryregion 1321 d) of the processor module configuration information 1321,whether or not migration from another processor module 1100 to acurrently managed LDEV has occurred (that is, it examines whether themanaged LDEV and the initial managed LDEV differ). If a migrated LDEVexists, the power management program 1133 executes S605, and otherwiseit ends the processor start control.

(S605) The power management program 1133 restarts the migrationprocessor destination module of FIG. 19. The power management program1133 then updates the information stored in the entry region 1322 ecorrespondent to the migration processor module to “active”. Inaddition, the power management program 1133 updates the informationstored in the entry region 1324 e correspondent to the processorscontained in the migration destination processor module 1100 to“active”, and updates the values stored in the entry region 1324 dcorrespondent to these processors to the number of cores that theseprocessors possess.

(S606) The power management program 1133 migrates the I/O commandprocess of the LDEV migrated using the method described with referenceto FIG. 19 to the migration source processor module 1100 of FIG. 19.

(S610) The power management program 1133 starts all sleeping cores of anactive processor of the migration destination processor module of FIG.19. Next, the power management program 1133 updates the informationstored in the entry region 1324 e correspondent to the active processor1110 comprising these cores 1111 from “core sleep” to “active”. Inaddition, the power management program 1133 updates the informationstored in the entry region 1324 c correspondent with this activeprocessor 1110 to the number of cores possessed by this processor 1110.

(S620) The power management program 1133 starts a sleep processor 1110of the migration destination processor module of FIG. 19. Next, thepower management program 1133 updates information stored in the entryregion 1324 e correspondent to this sleep processor 1110 to “active”. Inaddition, the power management program 1133 updates the informationstored in the entry region 1324 c correspondent to this sleep processor1110 to the number of cores possessed by this processor 1110.

During these series of processings, the power management program 1133acquires the control memory module 1320 lock and prohibits access to thecontrol memory module 1320 by another power management program 1133.

FIG. 21 is a flow chart of processor fault recovery processing.

(S700) When the fault recovery program 1134 fails to receive a heartbeatsignal from another active processor module 1100 in a fixed time periodor longer, or when notification of fault generation is provided, theexistence of a fault is detected in the processor module 1100 of thenotification source thereof or in the heartbeat signal transmissionsource thereof. This processor module 1100 is hereinafter referred to asa “fault processor module 1100”.

(S701) The fault recovery program 1134 selects a migration destinationprocessor module 1100. For example, the fault recovery program 1134selects the active processor module 1100 of lowest load from the one ormore active processor modules 1100.

(S702) The fault recovery program 1134 issues a command to the front-endmodule 1200 to transfer the I/O command process being executed by thefault processor module 1100 to the migration destination processormodule 1100 selected in S701. In response to the command from the faultrecovery program 1134, the FE data transfer program 1232 of thefront-end module 1100 updates the LUN managed by the fault processormodule 1100 to the LUN managed by the migration destination processormodule 1100 (in other words, updates the routing information 1231). TheFE data transfer program 1232 then initiates an I/O command transfercontrol in accordance with the updated routing information 1231.

(S703) The fault recovery program 1134 appends the number of the LDEVmanaged by the fault processor module 1100 to the entry region 1321 ccorrespondent to the migration destination processor module 1100. Inaddition, the power management program 1133 appends the performancerequirement of the LDEV managed by the fault processor module 1100 tothe value stored in the entry region 1322 c correspondent to themigration destination processor module 1100 and, furthermore, updatesthe information stored in the entry region 1322 e correspondent to thefault processor module 1100 to “fault”.

(S704) Finally, the fault recovery program 1134 cuts off the powersupply to the fault processor module 1100 (in other words, blocks orputs the fault processor module 1100 to sleep).

A description of a first embodiment of the present invention is givenabove. While as an example method of power management this embodimentdescribes the use of a method based on putting a processor module 1100to sleep, suppression of actuation frequency is also possible.

Second Embodiment

A second embodiment of the present invention will be hereinafterdescribed. The configuration of the computer system of this secondembodiment is substantially identical to that of the first embodimentand, accordingly, a description thereof has been omitted.

FIG. 22 is a diagram showing a schema of the second embodiment.

In the second embodiment, the power consumption of the cache memorymodule 1340 is reduced. The actuation of the cache memory module 1340will be described. The storage system 100 increases the speed of the I/Ocommand process from the host 200 by storing I/O data (read/write dataaccompanying I/O commands from the host 200) in the cache memory module1340 as cache data 1341. In data writing, the storage system 100 holdsthe I/O data as cache data 1341 and performs I/O data write to a diskunit 2000 non-synchronously with receipt of I/O commands. In addition,in data reading, the storage system 100 transfers the cache data to thehost 200 during a cache hit. The “cache hit” referred to here denotesfinding of I/O data associated with an I/O command from the cache memorymodule 1340.

The storage system 100 achieves increased data read speed by increasingthe capacity of the cache memory module 1340 and increasing the cachehit rate. The cache hit rate referred to here denotes the probabilitythat a cache hit will occur during the I/O command process. A largecapacity cache memory module 1340 carries with it an inherent concern ofincreased power consumption.

Thereupon, the storage system 100 of the second embodiment puts apartial region of the cache memory module 1340 to sleep when the numberof I/O commands is low and, accordingly, power consumption is reduced.

In the second embodiment, the sleep of the cache memory module 1340 isactualized by the following method.

The processor module 1100 on which the power management is beingexecuted monitors the number of I/O commands per unit capacity of thecache memory module 1340. When the number of I/O commands of theprocessor module 1100 is equal to or less than a threshold value, amemory block of low access frequency is put to sleep. The memory blockreferred to here denotes a physically or logically divided unit of thecache memory module 1340 on which a sleep control can be performed.

The processor module 1100, prior to the memory block being put to sleep,destages the unwritten cache data 1341 stored in this memory block to adisk unit 2000. The processing executed by the processor module 1100which involves destaging of the unwritten cache data 1341 prior to thememory block being put to sleep in order to prevent data loss is anillustrative example. In addition to this, prior to the memory blockbeing put to sleep by the processor module 1100, the unwritten cachedata 1341 can be migrated to another memory block (memory block in whichno cache data exists or memory block in which cache data that may beoverwritten is stored).

The destaging need not be performed when a non-volatile memory such as aflash memory is employed as the cache memory module. In this case, ifthe cache data of the sleep memory block is to be accessed, theprocessor module 1100 restarts the memory block and accesses the memoryblock after this start is completed.

In addition, prior to putting the memory block to sleep, the processormodule 1100 confirms that the access performance estimate followingsleep will meet the LDEV performance requirement. The access performancereferred to here denotes the maximum number of I/O accesses processableper second. The number of I/O accesses denotes the number of accesses ofthe cache memory module 1341 or a disk unit 2000 and constitutes a sumof the number of cache hits and the number of cache misses. The “cachemiss” referred to here denotes the access-target cache data stored inthe cache memory module 1340.

In addition, the storage system 100 receives a low access thresholdvalue and a high access threshold value from the service processor 3000.A storage administrator is able to set a trade-off between performanceand energy-saving power effect. While in this case a comparison of thelow access threshold value and high access threshold value is made with,for example, the number of I/O commands per unit capacity, a comparisonwith the total number of accesses of the cache memory module 1340 mayalso be made.

The second embodiment will be hereinafter described in detail.

The program and various data of the storage system 100 of the secondembodiment are described with reference to FIG. 23. A description of theelements thereof identical to those of the first embodiment has beenomitted. The data and programs indicated by the thick line in thediagram denote data and programs not present in the first embodiment ordata and programs different to those of the first embodiment.

In addition to the processings of the first embodiment, the I/O commandprocess program 1131 monitors the number of I/O commands and cache hitrate of the cache memory as a whole and writes this regularly in alater-described cache memory module information 1328. In addition, theI/O command process program 1131 monitors the number of cache hits ofeach memory block and records this regularly in the later-describedmemory block information 1329.

The power management program 1133 regularly implements a later-describedcache memory sleep control. The particulars of the cache memory sleepcontrol will be described later with reference to FIG. 26 and FIG. 27.In addition, when a sleep memory block exists, the power managementprogram 1133 regularly performs a cache memory start control. Theparticulars of the cache memory start control will be described laterwith reference to FIG. 28.

The cache memory module information 1328 and memory block information1329 will be described later with reference to FIG. 24 and FIG. 25.

The management I/F program 3031 displays a management screen on adisplay 3040. A storage administrator inputs a low access thresholdvalue and a high access threshold value of a later-described cachememory module 1340 by way of the management screen. The management I/Fprogram 3031 sends to a processor module 1100, as a management command,a command containing the management contents (input low access thresholdvalue and high access threshold value).

FIG. 24 shows the configuration of cache memory module information 1328.

The cache memory module information 1328 which is provided as, forexample, a table, contains information related to the performance andoperational state and setting of the cache memory module 1340. The cachememory module information 1328 comprises an entry region 1328 a to anentry region 1328 h.

The maximum number of I/O accesses (cache hit performance) processableper unit time (for example, per second) by the storage system 100 duringcache hit is stored in the entry region 1328 a. The maximum number ofI/O accesses (cache miss performance) processable per second by thestorage system 100 during cache miss is stored in the entry region 1328b. The cache hit rate is stored in the entry region 1328 c. The numberof I/O commands received from a host of the most recent 1-second periodis stored in the entry region 1328 d. The size of the active memoryregion of the cache memory module 1340 (sum total of size of non-sleepmemory blocks, hereinafter active memory size) is stored in the entryregion 1328 e. The threshold value (low access threshold value) servingas a reference for whether or not the access frequency to the cachememory module 1340 is a low access frequency is stored in the entryregion 1328 f (as an example method for appraising the access frequencyof the cache memory module 1340 the number of I/O commands per secondper megabyte of cache memory module is employed in this embodiment). Thethreshold value serving as a reference as to whether or not the cachememory module 1340 access frequency is a high access frequency (highaccess threshold value) is stored in the entry region 1328 g. The numberof I/O commands (performance requirement) requested for processing persecond by the storage system 100 is stored in the entry region 1328 h.This performance requirement is the sum total of the performancerequirement of all the LDEV existing in the storage system 100.

The cache hit performance (entry region 1328 a) and cache missperformance (entry region 1329 b) may be set manually by anadministrator or storage administrator of the storage system 100, or itmay be automatically computed by the processor module 1100 fromoperation results of device specifications.

FIG. 25 shows the configuration of memory block information 1329.

The memory block information 1329 which is provided as, for example, atable, contains information related to the configuration and operationalstate of each memory block. The memory block information 1329 comprisesan entry region 1329 a to entry region 1329 e for each memory block.

A memory block identifying number (memory block number) is stored in theentry region 1329 a. A memory block head physical address (initialaddress) of the cache memory module 1340 is stored in the entry region1329 b. The memory block size (region size, the unit thereof being, forexample, a megabyte) is stored in the entry region 1329 c. The number ofcache hits of the memory block per unit time (for example, per second)is stored in the entry region 1329 d. Information expressing the memoryblock state such as, for example, “active”, “sleep” and so on is storedin the entry region 1329 e.

Next, the various processings executed by the second embodiment will bedescribed with reference to FIG. 26 to FIG. 28.

FIG. 26 is a flow chart of cache memory sleep control processing.

(S800) The power management program 1133 reads cache memory moduleinformation 1328, memory block information 1329 and power managementinformation 1326 from the control memory module 1320.

(S801) The power management program 1133 calculates the per megabyteaccess frequency of the cache memory module 1340 from a quotient of thenumber of I/O commands (entry region 1328 d) and active memory size(entry region 1328 e) of the cache memory module information 1328. Thepower management program 1133 compares the calculated access frequencywith a low access threshold value (entry region 1328 f) executing S802when the access frequency is equal to or less than the low accessthreshold value, and otherwise ending the cache memory sleep control.

(S802) The power management program 1133, referring to the memory blockinformation 1329, selects the active memory block of lowest cache hitnumber (value stored in the entry region 1329 d) as a sleep target.

(S803) The power management program 1133 calculates a performanceestimate following migration based on cache hit performance a (entryregion 1328 a), cache miss performance b (entry region 1328 b), cachehit rate c (entry region 1328 c), active memory size d (entry region1328 e) and sleep target memory block size e (entry region 1329 c) ofthe cache memory module 1340. The power management program 1133calculates a cache hit rate estimate x and a performance estimate yfollowing sleep based on the following (Equation 1) and (Equation 2):x=c×(d−e)/d  (Equation 1)y=a×x+b×(1−x)  (Equation 2).

(S804) The power management program 1133 compares the performanceestimate y obtained in S803 with the performance requirement (entryregion 1328 h) executing S805 when the performance estimate y is equalto or greater than the performance requirement, and otherwise ending thecache sleep control.

(S805) The power management program 1133 executes cache memory sleep. Asa result, the sleep target memory block selected in S802 is put tosleep. The particulars of cache memory sleep will be described laterwith reference to FIG. 27.

FIG. 27 is a flow chart of cache memory sleep processing.

(S900) The power management program 1133, referring to the cache table1327, examines whether or not the data block stored in the sleep targetmemory block is an unwritten data block in a disk unit 2000. If thisdata block is unwritten, the power management program 1133 destages thisunwritten data block to the disk unit 2000.

(S901) The power management program 1133 deletes information related tothe sleep target memory block from the cache table 1327. In addition,the power management program 1133 notifies all processor modules 1100 ofthe sleep target memory block identifying number. In the processormodule 1100 receiving this notification, the power management program1133 deletes information related to sleep target memory block (memoryblock corresponding to the notified identifying number) from the cachetable copy 1134.

(S902) The power management program 1133 updates the information storedin the entry region 1329 e of the memory block information 1329 to“sleep”. In addition, the power management program 1133 updates theactive memory size (entry region 1328 e) of the cache memory module 1328to a value arrived at by deduction of the region size of the sleeptarget memory block (entry region 1329 c). Finally, the power managementprogram 1133 puts the sleep target memory block to sleep.

FIG. 28 is a flow chart of cache memory start control processing.

(S1000) The power management program 1133 acquires cache memory module1340 information in the same way as described by S800.

(S1001) The power management program 1133 calculates the cache memorymodule 1340 access frequency in the same way as described by S801. Thepower management program 1133 compares the calculated access frequencywith a high access threshold value (entry region 1328 g) executing S1002when the access frequency is equal to or greater than the high accessthreshold value, and otherwise ending the cache memory start control.

(S1002) The power management program 1133 selects a single sleep memoryblock and restarts this sleep memory block. The power management program1133 updates the information of the memory block information 1329 storedin the entry region 1329 e correspondent to the memory block to bestarted to “active”. In addition, the power management program 1133updates the active memory size (entry region 1328 e) of the cache memorymodule information 1328 to a value obtained by addition of the regionsize of the memory block to be started up (entry region 1329 c).

A description of a second embodiment of the present invention is givenabove. Instead of, or in addition to the memory blocks being put tosleep as described in this embodiment, the cache memory module can beput to sleep in regions logically divided into LDEV.

Third Embodiment

A third embodiment of the present invention will be hereinafterdescribed. The configuration of the computer system of this thirdembodiment is substantially identical to that of the first embodimentand, accordingly, a description thereof has been omitted.

FIG. 29 is a diagram showing a schema of the third embodiment.

In this third embodiment the power consumption of the disk unit 2000 isreduced.

In the disk unit 2000, one or more LDEV are prepared for each RAID Groupconfigured from a plurality of disks 2010 and I/O data is stored in theLDEV. The storage system 100 requires a large number of disks 2010 tostore a large volume of data and, accordingly, the power consumptionthereof is a problem. Accordingly, in the third embodiment, the storagesystem 100 puts the disks 2010 from which a RAID Group is configured andfor which there is no fixed time data input/output to sleep and,accordingly, power consumption is reduced. For ease of understanding ofthe description provided hereinafter, the sleep of the disks 2010 fromwhich a RAID Group is configured is expressed simply as RAID Groupsleep.

Consideration of RAID Group power consumption reduction raises theproblems of, for example, (Problem 1) and (Problem 2) noted below.

(Problem 1) When an LDEV from which a sleep RAID Group is formed exists,all disks from which the sleep RAID Group is configured must berestarted on each occasion of data input/output to this LDEV inaccordance with an I/O command from a host 200. Accordingly, a slowingof response speed to the host 200 occurs. In addition, when a RAID Groupis started on each occasion of data input/output to an LDEV, dependingon the frequency of this data input/output, there is an inherent concernthat more power than when the RAID Group is in constant operation willbe consumed.

(Problem 2) A storage administrator cannot implement a trade-off betweenperformance and power amount reduction.

The following means (Means 1) and (Means 2) are administered in thisthird embodiment to resolve the problems (Problem 1) and (Problem 2)described above.

(Means 1) A controller 1000, subsequent to migrating all LDEV containedin this RAID Group to another RAID Group when a low load RAID Group isfound, puts the low load RAID Group to sleep. The LDEV migrationreferred to here denotes the physical storage location of the LDEV beingtransparently altered by a host. The method of RAID Group load appraisalinvolves a comparison between the number of disk accesses processableper unit time (for example, per second) and the number of current diskaccesses. In addition, the number of disk accesses refers to the numberof accesses to an actual storage unit and does not include access tocache data. As a result, the sleep RAID group is not accessed by thehost 200, and the need for restart thereof becomes unnecessary.

There are inherent concerns accompanying LDEV migration of high load onthe migration destination RAID Group and LDEV performance requirementnot being met. Accordingly, as further means, prior to LDEV migration,the controller 1000 judges whether or not the load on the migrationdestination RAID Group will be a high load and whether or not, when LDEVmigration is performed, the LDEV performance requirement will be met,and executes LDEV migration if the load will not be high and the LDEVperformance requirement will be met.

In addition, the LDEV migration involves a load being placed on thecontroller 1000 and the disks 2010. Furthermore, it is not necessarilythe case that all RAID Groups have the same reliability and performance.Accordingly, in contradiction to the aims of a storage administrator,there is a concern that a temporary rise in load on the storage system100 and change in the LDEV reliability and performance will occur as aresult of LDEV migration. Accordingly, as further means, the storagesystem 100 provides the storage administrator with a warning messagewhereupon, by selection of whether or not RAID Group sleep should beenabled, LDEV migration that contradicts the aims of the storageadministrator is prevented.

(Means 2) The storage system 100 receives a RAID Group for which sleepis to be enabled, a low access threshold value, and a high accessthreshold value from the service processor 3000. The storageadministrator is able to set a trade-off between performance and amountof power reduction.

The third embodiment will be hereinafter described in detail.

The programs and various data of the storage system 100 in the thirdembodiment will be described with reference to FIG. 30. A description ofthe elements identical to those of the first embodiment has beenomitted. The data and programs indicated by the thick line of thediagram denote data and programs that exist in the first embodiment ordata and programs that differ from the first embodiment.

LDEV migration processing is performed as a result of a processor 1110executing an LDEV migration program 1137 stored in a memory module 1130.The LDEV migration processing can be actualized using, for example,integrated circuit-based hardware.

In addition to the processings described in the first embodiment, theI/O command process program 1131 writes the number of I/O commands ofeach LDEV of the most recent 1-second period in a later-described LDEVstate information 1330. In addition, the I/O command process program1131 regularly (or irregularly) examines the number of disk accesses andfree capacity of the RAID Groups, and updates the later-described RAIDGroup information 1331.

The power management program 1133 regularly (or irregularly) executes adisk sleep control. The particulars of the disk sleep control will bedescribed later with reference to FIG. 34 and FIG. 35. In addition, thepower management program 1133, when a sleep RAID Group exists, regularly(or irregularly) executes a disk start control. The particulars of thedisk start control will be described later with reference to FIG. 36.

The LDEV migration program 1137 migrates a designated LDEV to adesignated RAID Group. The LDEV migration program 1137, prior tomigrating the LDEV, secures a region of a capacity the same as the LDEVto be migrated to the migration destination RAID Group. Next, the LDEVmigration program 1137 copies the LDEV data to be migrated to thesecured region. The LDEV migration program 1137 then updates each of thevalues of the migration LDEV RAID Group number (1325 b) and initialaddress (1325 c) of the LDEV configuration information 1325 and updatesthe migration destination RAID Group number and initial address of thesecured region. After this, the LDEV migration program 1137 updates theLDEV configuration information 1325 stored in the shared memory module1300. At this time, the LDEV migration program 1137 issues a command toall processor modules 1100 to update the LDEV configuration informationcopy 1135. Finally, the LDEV migration program 1137 erases the datastored in the migration destination LDEV.

The LDEV state information 1330, RAID Group information 1331 and powermanagement information 1326 of the control memory module 1320 will bedescribed with reference to FIG. 31 to FIG. 33.

In addition to the processings of the first embodiment, the managementI/F program 3031 displays on a display 3040 a management screen intowhich the RAID Group for which sleep is to be enabled, warning settings,and a low load threshold value and high load threshold value for eachRAID Group are input. In addition, the management I/F program 3031notifies the processor module 1100 of, as a management command, acommand containing the various information input by way of thismanagement screen.

Next, the configuration of various information will be described withreference to FIG. 31 to FIG. 33.

FIG. 31 is a diagram showing the configuration of LDEV state information1330.

The LDEV state information 1330 which is provided as, for example, atable, contains information related to LDEV operational state. The LDEVstate information 1330 comprises, for each LDEV, entry regions 1330 aand 1330 b. The LDEV identifying number (LDEV number) is stored in theentry region 1330 a. The number of I/O commands to an LDEV in the mostrecent 1-second period is stored in the entry region 1330 b.

FIG. 32 is a diagram showing the configuration of RAID Group information1331.

The RAID Group information 1331 which is provided as, for example, atable, contains information related to the performance, configurationand operational state of a RAID Group. The RAID Group information 1331comprises, for each RAID Group, an entry region 1331 a to entry region1331 j.

A RAID Group identifying number (RAID Group number) is stored in theentry region 1331 a. The number of disk accesses processable by a RAIDGroup per second (RAID Group capacity performance) is stored in theentry region 1331 b. The number of disk accesses requested by a RAIDGroup per second, (RAID Group performance requirement) is stored in theentry region 1331 c. The RAID Group performance requirement is a valuearrived at by multiplying a predetermined coefficient with the sum totalof the performance requirement of one or more LDEV of the RAID Group.The coefficient is generally determined on the basis of, for example,cache miss rate. The LDEV identifying number of a RAID Group is storedin the entry region 1331 d. The identifying number of an LDEV initiallyformed in a RAID Group is stored in the entry region 1331 e. The numberof disk accesses per second (RAID Group current performance) is storedin the entry region 1331 f. The size of a currently non-used storageregion (free capacity) is stored in the entry region 1331 g. Thethreshold value (low load threshold value) serving as a reference as towhether or not RAID Group load is a low load is stored in the entryregion 1331 h. The threshold value (high load threshold value) servingas a reference as to whether or not RAID Group load is a high load isstored in the entry region 1331 i. Information indicating the RAID Groupstate such as, for example “active” or “sleep” is stored in the entryregion 1331 j.

RAID Group capacity performance may be set manually by a maintenancepersonal or storage administrator of the storage system 100, or it maybe set automatically on the basis of operation results or devicespecifications.

FIG. 33 is a diagram showing the configuration of the power managementinformation 1326 of the third embodiment.

The power management information 1326 contains information related topower management. The power management information 1326 comprises anentry region 1326 b and an entry region 1326 c. A sleep enable RAIDGroup (RAID Group in which sleep is to be enabled) identifying number isstored in the entry region 1326 b. Information expressing whether or notnotification is to be provided to a storage administrator prior to aRAID Group being put to sleep is stored in the entry region 1326 c.

The various processings performed in this third embodiment will behereinafter described with reference to FIG. 34 to FIG. 36.

FIG. 34 is a flow chart of disk sleep control processing.

(S1100) The power management program 1133 reads LDEV configurationinformation 1325, LDEV state information 1330, RAID Group information1331 and power management information 1326 from the control memorymodule 1320.

(S1101) The power management program 1133, referring to the power ismanagement information 1326, specifies one or more sleep enable RAIDGroup, specifies the RAID Group performance (entry region 1331 b) andthe RAID Group current performance (entry region 1331 f) of a sleepenable RAID Group, and calculates the load on a sleep enable RAID Group.The load is determined on the basis of, for example, a ratio of RAIDGroup current performance to RAID Group capacity performance (forexample, RAID Group current performance as a percentage of RAID Groupcapacity performance). The power management program 1133 compares theload on a sleep enable RAID Group with the low load threshold value(entry region 1331 h) executing S1102 when there is at least one sleepenable RAID Group of load equal to or less than the low load thresholdvalue, and otherwise ending the disk sleep control.

(S1102) The power management program 1133 selects one of the RAID Groupsjudged in S1101 as being of low load (sleep enable RAID Group of loadequal to or less than the low load threshold value) as a RAID Groupcandidate to be put to sleep (sleep RAID Group candidate).

(S1103) The power management program 1133, referring to the RAID Groupinformation 1331, specifies the LDEV existing in the sleep RAID Groupcandidate selected in S1102. The power management program 1133 searchesthe RAID Group for the LDEV of the specified LDEV that will serve as amigration destination. The particulars of the LDEV migration destinationsearch will be described later with reference to FIG. 35.

(S1104) Based on the result of S1103, the power management program 1133executes S1105 when a migration destination exists in all LDEV, andotherwise ends the disk sleep control.

(S1105) The power management program 1133 executes S1106 when a warningsetting of the power management information 1326 (entry region 1326 c)is enabled, and otherwise executes S1107.

(S1106) The power management program 1133 sends to the service processor3000 a warning message containing an identifying number of the RAIDGroup to be put to sleep and an identifying number of the RAID Groups inwhich there are LDEV migration destinations. Upon receipt of thiswarning message, the management I/F program 3031 of the serviceprocessor 3000 displays the warning message in a display 3040 and asksthe storage administrator if sleep is to be enabled. The storageadministrator confirms the contents of the aforementioned warningmessage noted and inputs whether or not the RAID Group sleep is to beenabled. The power management program 1133 executes S1107 when sleep isenabled by the storage administrator, and otherwise ends the disk sleepcontrol.

(S1107) The power management program 1133 migrates all LDEV of the sleepRAID Group candidates (migration source RAID Groups) selected in S1102to respective migration destination RAID Groups found by the searchprocessing of S1103. The actual migration processing is executed by theLDEV migration program 1137. Following completion of the LDEV migration,the LDEV migration program 1137 provides notification to the powermanagement program 1133 of LDEV migration completion.

(S1108) Upon receipt of this notification (in other words, followingmigration completion of all migration target LDEV), the power managementprogram 1133 accesses the RAID Group information 1331 and, for eachmigration source RAID Group and migration destination RAID Group,updates the RAID Group performance requirement (entry region 1331 b),LDEV identifying number (entry region 1331 d), free capacity (entryregion 1331 f) and RAID Group state (entry region 1331 j).

FIG. 35 is a flow chart of the LDEV migration destination searchprocessing.

(S1200) The power management program 1133 selects a RAID Group as anassessment target for LDEV migration destination. The power managementprogram 1133 selects the RAID Groups on which an assessment has not yetbeen carried out as an assessment target in order of low load RAID Groupas calculated by S1100.

(S1201) The power management program 1133, referring to the LDEVconfiguration information 1325 and RAID Group information 1331,specifies and compares the LDEV region size (1325 d) and assessmenttarget RAID Group free capacity (1331 g). The power management program1133 executes S1202 when the LDEV region size is equal to or less thanthe free capacity of the assessment target RAID Group, and otherwiseexecutes S1210.

(S1202) The power management program 1133, referring to the LDEV stateinformation 1330 and RAID Group information 1331, calculates a loadestimate following migration based on a sum of the number of I/Ocommands of the LDEV being migrated (entry region 1330 b) and the numberof disk accesses of the assessment target RAID Group (entry region 133f). When the RAID Group serving as the assessment target constitutes atemporary migration destination for another LDEV, the number of I/Ocommands of this LDEV (entry region 1330 b) is also added to theestimate of number of accesses following migration. Next, the powermanagement program 1133, referring to the RAID Group information 1331,calculates a ratio of assessment target RAID Group capacity performance(entry region 1331 b) and estimated number of disk accesses followingmigration (for example, a percentage of the estimate of the number ofdisk accesses following migration to the capacity performance thereof),in other words, a load estimate. The power management program 1133compares the load estimate with the high load threshold value andexecutes S1203 when the load estimate is equal to or higher than thehigh load threshold value, and otherwise executes S1210.

(S1203) The power management program 1133, referring to the LDEVconfiguration information 1325 and RAID Group information 1331,determines a performance requirement estimate following migration basedon a sum of the performance requirement of the assessment target RAIDGroup (entry region 1331 d) and performance requirement of the LDEV tobe migrated (1325 f). When the RAID Group serving as the assessmenttarget constitutes a temporary migration destination for another LDEV,the performance requirement of this other LDEV (entry region 1330 b) isalso added to the performance requirement estimate following migration.The power management program 1133, referring to the RAID Groupinformation 1331, executes S1204 when the performance requirementestimate is less than the RAID Group capacity performance (1331 b), andotherwise executes S1210.

(S1204) The power management program 1133, taking the assessment targetRAID Group as a temporary migration destination, ends the LDEV migrationdestination search.

(S1210) The power management program 1133 executes S1200 when anon-assessed RAID Group exists, and otherwise ends the LDEV migrationdestination search.

FIG. 36 is a flow chart of disk start control processing.

(S1300) The power management program 1133, similarly to S1100, readsinformation related to RAID Groups from the control memory module 1320.

(S1301) The power management program 1133, similarly to the method ofS1101, calculates the load estimate of the RAID Group of which an LDEVis being migrated. The power management program 1133 ends the disk startcontrol when the load estimate of all migration destination RAID Groupsis equal to or less than the high load threshold value (entry region1331 g), and otherwise executes S1302.

(S1302) The power management program 1133 restarts the LDEV migrationsource RAID Group. Next, the power management program 1133 updates theinformation of the RAID Group information 1331 correspondent to therestarted RAID Group recorded in the entry region 1331 j to “active”. Ifthe LDEV migration source RAID Group has been already started, the powermanagement program 1133 is not executed.

(S1303) The power management program 1133, using the same method asS1106, migrates an LDEV to a source RAID Group.

A description of a third embodiment of the present invention is givenabove. Control of reliability and performance can be added to the LDEVmigration destination RAID Group search processing.

Fourth Embodiment

The configuration of a computer system pertaining to a fourth embodimentof the present invention will be described with reference to FIG. 37.

In this fourth embodiment, an externally-connected storage system 600 isconnected to the storage system 100. The remaining configuration issubstantially identical to the first embodiment and, accordingly, adescription thereof has been omitted.

The externally-connected storage system 600 is connected to an internalback-end module 1600 of the storage system 100 employing Fiber Channelor FCP. The back-end module 1600 performs data transfer between thestorage system 100 and the externally-connected storage system 600 inaccordance with a command from the processor module 1100. Theexternally-connected storage system 600 comprises a function forimplementing sleep or restart in response to an externally-receivedsleep command or start command.

FIG. 38 is a diagram showing a schema of the fourth embodiment.

In this fourth embodiment, the power consumption of theexternally-connected storage system 600 is reduced.

The externally-connected storage system 600 will be described. Similarlyto the storage system 100, the externally-connected storage system 600constitutes a storage system that itself comprises a function forproviding LDEV to the host 200. The storage system 100 implements avirtual provision of the LDEV of the externally-connected storage system600 to the host 200 as its own LDEV. When an I/O command is received atthe LDEV of the externally-connected storage system 600, the storagesystem 100 performs a virtual control of the externally-connectedstorage system 600 as a RAID Group of the virtual storage system 100.

A plurality of externally-connected storage systems 600 are connected tothe storage system 100, a simplification of the management thereof beingable to be achieved by centralized management. A problem inherent tothis kind of system is the power consumption of the externally-connectedstorage system 600. In this fourth embodiment, power consumption isreduced by an externally-connected storage of low access frequency ofthe externally-connected storage systems 600 being put to sleep.

In putting an externally-connected storage system 600 to sleep, asubstantial occurrence of the problem associated with putting a RAIDGroup to sleep of the third embodiment can be considered. A resolutionto this problem is achieved in the fourth embodiment by the followingmeans.

That is, the storage system 100 migrates an LDEV of anexternally-connected storage system 600 to another externally-connectedstorage system 600 or to a RAID Group of its own disk unit 2000, andthen puts the externally-connected storage system 600 to sleep. Thestorage system 100 performs a power management similar to that of thethird embodiment based on managing the externally-connected storagesystem 600 as a virtual RAID Group.

The main points of difference to the third embodiment will behereinafter described.

The programs and various data of the storage system 100 of the fourthembodiment will be hereinafter described with reference to FIG. 30.

The I/O command process program 1131, when an I/O command is received atthe LDEV provided by an externally-connected storage system 600, issuesa command to the back-end module 1600 to perform the necessary datatransfer.

The power management program 1133 deals with its own RAID Group and theexternally-connected storage system 600 in the same way as described forthe RAID Group of the third embodiment.

LDEV migration program 1137 regards the externally-connected storagesystem 600 as a virtual RAID Group and executes LDEV migration betweenexternally-connected storage systems 600 and between anexternally-connected storage and the storage system 100. The LDEVmigration program 1137 calls the function of the externally-connectedstorage system 600 necessary for LDEV migration such as LDEV definitionand LDEV deletion using a method designated by an externally-connectedstorage system 600.

In addition to LDEV configuration information 1325, RAID Groupinformation 1331, LDEV state information 1330, and information relatedto RAID Groups, information related to the externally-connected storagesystems 600 are stored in the shared memory module 1300.

In addition to the processings of the third embodiment, the managementI/F program 3031 displays in the display 3040 a management screenrelated to a RAID Groups of an externally-connected storage for whichsleep is to be enabled. The management I/F program 3031 notifies aprocessor module 1100 of, as a management command, a command containinginformation input by way of the management screen.

A description of a fourth embodiment of the present invention is givenabove. Instead of the whole of the externally-connected storage system600 being put to sleep, a part thereof such as, for example, acontroller or a cache memory or disk may be put to sleep.

Fifth Embodiment

The configuration of a computer system related to a fifth embodiment ofthe present invention will be hereinafter described with reference toFIG. 39.

In this fifth embodiment, the computer system is configured from two ormore storage systems 100, one or more hosts 200, one or more managementservers 300, a storage network 400 and a management network 500. Thesystem configuration between the storage system 100, host 200 andmanagement server is substantially identical to that of the firstembodiment. Management information and data is transferred between theplurality of storage systems 100 to which controllers 1000 are connectedemploying FC and FCP. The interface and protocol between the controllers1000 are illustrative examples, and other interfaces and protocols maybe employed. The access path from the host 200 to the LDEV storagesystem 100 is controlled by a path control module 2001 actuated by thehost 200. The access path refers to the network path used when the hostaccesses an LDEV. While the use of hardware as the path control module2001 is cited in this example, a computer program executed by aprocessor may also be employed.

The storage system 100 of this fifth embodiment comprises a function bywhich it is itself put to sleep by a controller 1000, and a function forits external restart. The hardware configuration thereof issubstantially identical to that of the first embodiment and,accordingly, a description thereof has been omitted.

Next, a schema of the fifth embodiment will be hereinafter describedwith reference to FIG. 40.

In the fifth embodiment, power consumption of the storage system 100 isreduced.

A greater amount of data storage and greater number of I/O commandprocessings are afforded by increasing the number of storage systems100. However, a problem inherent to increasing the number of storagesystems carries is a problem of increased power consumption.

In the fifth embodiment, a storage system 100 migrates an LDEV of a RAIDGroup of low access to another storage system 100 and puts the RAIDGroup to sleep. In this case, the occurrence of the following problemscan be considered.

First, when an LDEV is migrated to another storage system 100, thenetwork path from the host 200 for accessing the LDEV in questionchanges. Accordingly, the LDEV migrated by the host 200 can no longer beaccessed.

In addition, similarly to the other embodiments, there are concerns thatthe load on the migration destination storage system 100 will be highand the LDEV performance requirement will not be met. Furthermore, thestorage administrator is unable to set a trade-off between performanceand energy-saving power effect.

The following means are administered in the fifth embodiment to resolvethese problems.

A storage system 100 migrates an LDEV of the low load RAID Group toanother storage system and puts the RAID Group to sleep. Theseprocessings are actualized as a result of the RAID Groups of all storagesystems being virtually regarded by a storage system 100 as its own RAIDGroups, and implementation of the processings identical to those of thethird embodiment. The storage system 100 executing the power managementprogram puts a storage system 100 to sleep when all RAID Groups aresleep.

When an LDEV is migrated to another storage system 100, the storagesystem 100 executing the power management program provides notificationto the host 200 of a migration LDEV identifying number and a migrationdestination storage system identifier. The host 200 comprises a pathcontrol module 2001, and the path control module 2001 receives thesenotifications. The path control module 2001 updates the access path tothe migrated LDEV in response to these notifications. The path controlmodule 2001 which, for example, constitutes a computer program executedby a processor of the host 200, refers to and updates the informationfor each LDEV expressing the LDEV number and identifier of the storagesystem in which the LDEV exists (information stored in a storageresource such as the memory of the host 200). When an I/O command inwhich the LDEV is designated is received from an application programexecuted by a processor of the host 200, the path control module 2001specifies the storage system in which this LDEV exists, or sends an I/Ocommand in which the LDEV is designated to a specified storage system.

The main points of difference with the third embodiment will behereinafter described, a description of the points of commonalitytherebetween being either omitted or abridged.

The programs and various data of the storage system 100 of the fifthembodiment will be described with reference to FIG. 30.

The power management program 1133 regularly (or irregularly) issues acommand to another storage system 100 to send LDEV configurationinformation 1331, LDEV state information 1330 and RAID Group information1331. The power management program 1133 of the other storage systemreceiving this command transfers this information from the controlmemory module 1320 to the storage system 100 on which the powermanagement processing is being executed. The power management program1133 of the storage system 100 to which this transfer of information hasbeen received combines this information and stores it as LDEVconfiguration information 1331, LDEV state information 1330 and RAIDGroup information 1331 of the control memory module 1320.

The LDEV migration program 1137, in association with another storagesystem 100, actualizes the LDEV migration between the storage systems100.

Information related to all storage systems 100 is contained in the LDEVconfiguration information 1325, LDEV state information 1330 and RAIDGroup information 1331 stored in the control memory module 1320 of thestorage system 100 on which the power management is being performed.

In addition to the processings of the third embodiment, the managementI/F program 3031 displays in a display 3040 a management screen of theRAID Groups for which sleep is to be enabled of another storage system100. In addition, the management I/F program 3031 notifies the processormodule 1100 of, as a management command, a command containinginformation input by way of the management screen.

Next, the various processings different to those of the third embodimentwill be described with reference to FIG. 34 to FIG. 36.

The power management program 1133 deals with RAID Groups of anotherstorage system 100 in which the RAID Groups are virtually recognized inthe same way as the RAID Groups of the third embodiment.

(S1108 of FIG. 34) When all RAID Groups of a storage system 100 aresleeping, the power management program 1133 issues a sleep command tothe controller 1000 of this storage system 100.

(S1302 of FIG. 36) When the migration destination storage system 100 issleeping, the power management program 1133 issues a command to restartthe storage system 100 of this migration destination.

(S1106 of FIG. 34 and S1303 of FIG. 36) The LDEV migration program 1137having received a command from the power management program 1133notifies the host 200 of the LDEV number and the storage systemidentifier of the migration destination storage system 100. The pathcontrol module 2001 of the host 200, subsequent to the receipt of thesenotifications, performs an access path switchover to the migrating LDEV.For example, when an I/O command in which a particular LDEV isdesignated is received from an application program (not shown in thediagram) on the host 200, the path control module 2001 sends the I/Ocommand in which this LDEV is designated to the migration destinationstorage system 100 indicated by the received storage system identifier.

A fifth embodiment of the present invention is described above.Replacing the storage system 100, the power management may be executedby a management server 300.

Sixth Embodiment

Two or more of the first to fifth embodiments may be combined.Accordingly, for example, both cache sleep and disk sleep can beperformed in a single storage system. However, in this case, a timingcontrol between the cache sleep and disk sleep must be executed. Morespecifically, for example, when disk sleep control processing isgenerated during cache sleep control processing, destaging of diskunwritten cache data (unwritten data to the disk) of the cache memorymodule 1340 and LDEV migration can be simultaneously generated. There isconcern that if the destaged destination LDEV of the disk unwrittencache data constitutes the LDEV to be migrated, destaging will beperformed during LDEV migration and the cache data will not reflected inthe LDEV of the migration destination RAID Group (that is, a concernthat the cache data will be lost).

Thereupon, in this sixth embodiment, one of either the cache sleep orthe disk sleep is implemented first, the processing of the other beinginitiated following completion of the processing implemented first. Theparticulars thereof will be described with reference to FIG. 41 (thenumbers within the < > of FIG. 41 express the sequence in which theprocessings are performed).

The disk sleep and cache sleep are taken as occurring essentiallysimultaneously. The migration target LDEV of the disk sleep and thedestage destination LDEV of the cache sleep are taken as LDEV1′.

The power management program 1133 stops the destaging of dirty cachedata from the cache memory module, and executes LDEV1′ migration to theLDEV migration program. Following completion of the LDEV1′ migration,the power management program 1133 updates the LDEV configurationinformation 1325 stored in the control memory module 1320 and the LDEVconfiguration information copy 1135 of the self-actuated processormodule. Following completion of the update of the LDEV configurationinformation 1325 and LDEV configuration information copy 1135, the powermanagement program 1133 initiates the stopped destaging. The destageddestination at this time is the LDEV1′ of the migration destination RAIDGroup. The power management program 1133 then updates the cache tablestored in the shared memory module and the cache table copy of theself-actuated processor module, and ends the processing.

The execution of the LDEV migration first in the description above isused only as an example, and the LDEV migration may instead be initiatedfollowing destaging. In addition, for example, which of either thedestaging or the LDEV migration is to be implemented first may bedetermined in accordance with, for example, whether or not the LDEVmigration destination is a remote storage system. For example, thedestaging may be implemented first when the LDEV migration destinationis a remote storage system, while on the other hand the LDEV migrationmay be executed first when the LDEV migration destination is a localstorage system (that is, when it is the same storage system).

Seventh Embodiment

When at least two of processor sleep, cache sleep and disk sleep are tobe performed, a storage administrator must set a trade-off (for example,low load threshold value, low access threshold value, high loadthreshold value, high access threshold value, and energy-saving powerlevel and so on) between the various sleeps. It is possible that astorage administrator will find this complicated.

Thereupon, the processing as shown in FIG. 42 is performed in theseventh embodiment.

That is, a policy management table 331 is stored in management server300 (or service processor 3000) storage resource. In the policymanagement table 331, for example as shown in FIG. 43, for each policythere is corresponding combination of set values used for the pluralityof types of sleep control. For example, for the policy value “A”, thereis correspondence between an energy-saving power level is “4”, high loadthreshold value “80%” and low load threshold value “30%” of processorsleep, high access threshold value “80%” and low access threshold value“30%” of cache sleep, sleep enable RAID Groups “1, 2, 3, 4, 5”, highload threshold value “80%”, low load threshold value “30%” and warningsetting “enable” of disk sleep.

The management server 300 (or service processor 3000) provides a GUI forediting the policy management table 331 and inputting the desired policyvalues of a storage administrator. A storage administrator inputs policyvalues and edits the policy management table 331 by way of this GUI.

When a policy value has been input by way of the GUI, the managementserver 300 (or service processor 3000), by way of a setting controlprogram (not shown in the diagram) executed by a processor of, forexample, the management server 300 (or service processor 3000),specifies the various set values of the policy management table 331correspondent to this policy value and sends a management commandcontaining the various designated set values to a processor module 1100.The processor module 1100 processes these management commands using amethod as outlined in the embodiments, and updates the power managementinformation 1326 or other information (for example, LDEV configurationinformation) stored in the control memory module 1320.

In this way, in this seventh embodiment, various settings of a pluralityof types of sleep control can be performed by a storage administratorbased on a simple inputting of a desired policy value of a plurality ofpolicy values.

While preferred embodiments of the present invention are describedabove, these represent illustrative examples only provided for thepurpose of describing the present invention and the gist of the presentinvention is not to be regarded as being limited to these embodiments.The present invention can be carried out in various other modes.

What is claimed is:
 1. A system comprising: a host computer; a firststorage system coupled to the host computer; and a second storage systemcoupled to the host computer, wherein each of the first storage systemand the second storage system comprises: a plurality of storage devicesconfiguring a plurality of RAID (Redundant Array of Inexpensive Disks)groups, one or more logical volumes being configured on storage spacesprovided by each of the RAID groups, one or more processors forprocessing input/output (I/O) requests from the host computer addressedto the logical volumes, and a cache memory for caching read/write dataaccompanied with the I/O requests, wherein each of the first storagesystem and the second storage system comprises a shared memory forstoring configuration information on the logical volumes beingconfigured on the RAID groups in both of the first storage system andthe second storage system, the information indicating which storagespaces of the RAID groups in the first storage system and the secondstorage system each of logical volumes is being configured on, whereinthe one or more processors in the first storage system are configured tostop destaging dirty cache data from the cache memory in the firststorage system, migrate all data in the logical volumes on one of theRAID group in the first storage system within storage spaces provided byone of the RAID groups in the second storage system during the stop ofdestaging, destage the dirty cache data from the cache memory in thefirst storage system to the storage spaces in the second storage system,update the configuration information on the migrated logical volumeswhere the migrating is executed, shift a state of the one of the RAIDgroup in the first storage system to a power-saving state, and notifythe host computer that the migrated logical volumes are migrated to thesecond storage system, and wherein the one or more processors in thesecond storage system are configured to update the configurationinformation on the migrated logical volumes.
 2. The system according toclaim 1, wherein the one or more processors in the first storage systemare configured to execute the migrating if a ratio of the number ofaccesses to the one of the RAID group in the first storage system perunit time to the number of processable accesses by the one of the RAIDgroup in the first storage system per unit time is less than apredetermined first threshold value.
 3. The system according to claim 2,wherein the one or more processors are configured to execute themigrating if a ratio of the number of estimated accesses to the one ofthe RAID group in the second storage system per unit time to the numberof processable accesses by the one of the RAID group in the secondstorage system per unit time when the migrating is executed, is lessthan a predetermined second threshold value.
 4. A method of migratingdata in a system, the system comprising: a host computer; a firststorage system coupled to the host computer; and a second storage systemcoupled to the host computer, wherein each of the first storage systemand the second storage system comprises a plurality of storage devicesconfiguring a plurality of RAID (Redundant Array of Inexpensive Disks)groups, one or more logical volumes being configured on storage spacesprovided by each of the RAID groups, one or more processors forprocessing input/output (I/O) requests from the host computer addressedto the logical volumes, and a cache memory for caching read/write dataaccompanied with the I/O requests, wherein each of the first storagesystem and the second storage system comprises a shared memory forstoring configuration information on the logical volumes beingconfigured on the RAID groups in both of the first storage system andthe second storage system, the information indicating which storagespaces of the RAID groups in the first storage system and the secondstorage system each of logical volumes is being configured on, themethod comprising: stopping, by the one or more processors in the firststorage system, destaging of dirty cache data from the cache memory inthe first storage system; migrating, by the one or more processors inthe first storage system, all data in the logical volumes on one of theRAID group in the first storage system within storage spaces provided byone of the RAID groups in the second storage system during the stoppingof destaging; destaging, by the one or more processors in the firststorage system, the dirty cache data from the cache memory in the firststorage system to the storage spaces in the second storage system;updating, by the one or more processors in the first storage system, theconfiguration information on the migrated logical volumes where themigrating is executed; shifting, by the one or more processors in thefirst storage system, a state of the one of the RAID group in the firststorage system to a power-saving state; notifying, by the one moreprocessors in the first storage system, the host computer that themigrated logical volumes are migrated to the second storage system; andupdating, by the one or more processors in the second storage system,the configuration information on the migrated logical volumes.
 5. Themethod according to claim 4, further comprising: executing, by the oneor more processors in the first storage system, the migrating if a ratioof the number of accesses to the one of the RAID group in the firststorage system per unit time to the number of processable accesses bythe one of the RAID group in the first storage system per unit time isless than a predetermined first threshold value.
 6. The method accordingto claim 5, further comprising: executing, by the one or moreprocessors, the migrating if a ratio of the number of estimated accessesto the one of the RAID group in the second storage system per unit timeto the number of processable accesses by the one of the RAID group inthe second storage system per unit time when the migrating is executedis less than a predetermined second threshold value.